Square root Definition and 383 Threads

In mathematics, a square root of a number x is a number y such that y2 = x; in other words, a number y whose square (the result of multiplying the number by itself, or y ⋅ y) is x. For example, 4 and −4 are square roots of 16, because 42 = (−4)2 = 16.
Every nonnegative real number x has a unique nonnegative square root, called the principal square root, which is denoted by





x


,


{\displaystyle {\sqrt {x}},}
where the symbol















{\displaystyle {\sqrt {~^{~}}}}
is called the radical sign or radix. For example, the principal square root of 9 is 3, which is denoted by





9


=
3
,


{\displaystyle {\sqrt {9}}=3,}
because 32 = 3 ⋅ 3 = 9 and 3 is nonnegative. The term (or number) whose square root is being considered is known as the radicand. The radicand is the number or expression underneath the radical sign, in this case 9.
Every positive number x has two square roots:





x


,


{\displaystyle {\sqrt {x}},}
which is positive, and






x


,


{\displaystyle -{\sqrt {x}},}
which is negative. Together, these two roots are denoted as



±


x




{\displaystyle \pm {\sqrt {x}}}
(see ± shorthand). Although the principal square root of a positive number is only one of its two square roots, the designation "the square root" is often used to refer to the principal square root. For positive x, the principal square root can also be written in exponent notation, as x1/2.Square roots of negative numbers can be discussed within the framework of complex numbers. More generally, square roots can be considered in any context in which a notion of the "square" of a mathematical object is defined. These include function spaces and square matrices, among other mathematical structures.

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  1. M

    Squared numbers and square root (Need help with explaination)

    Can anyone tell me why for example the speed of light is squared in "E=mc^2" ? Also what does square root mean and why is it in certain equations like for example time dilation? What happens if you exclude the square root and the y^x in a equation? I am still studying high school physics, but...
  2. T

    MHB How can you factor out x from the original term?

    In a text, We have this: $\sqrt{2x^2 + 1}$ is equal to $x \sqrt{2 + \frac{1}{x}}$ I am confused as to how to factor out x from the original term.
  3. C

    MHB What is the Square Root Property in Mathematics?

    Dear everyone, I have a question about a property of square root. $${\frac{1}{x}\sqrt{x^2}}$$$\implies$ $\sqrt{\frac{x^2}{x^2}}$=$\left| 1 \right|$ Is that property of a square root? Since $$\sqrt{x^2}$$= $\left| x \right|$.
  4. PcumP_Ravenclaw

    Square root of 2 divided by 0 is rational?

    Dear All, Please help me understand how ## \sqrt{2} ## divide by 0 is rational as stated in the excerpt from alan F beardon's book?
  5. Z

    MHB How can we simplify this expression involving square roots?

    4\sqrt{n^{2}}+\sqrt{m^{2}n-\sqrt{4n^{2}}}-\sqrt{mn^{2}} I don't even know where to start, I know the teacher said to distribute but distibute what?
  6. O

    MHB Simplifying a square root in a fraction, part of midpoint formula

    I have: sq rt 2 +sq rt 2 over 2 , sq rt 5 + sq rt 5 over 2 I got (sq rt 4 over 2, and 0) = 1, 0 but the answer is actually (sq rt 2, 0) so is my answer still wrong?
  7. V

    How do I linearize a square root graph?

    Homework Statement These are the Points. X values: 0, 1.98, 3.96, 5.94, 7.92, 9.9 Y values: 1.98, 7.13, 9.08, 11.04, 12.57, 14.51 I need to find the original equation and the linear equation. I can't seem to find the line for square root graphs. 2. The attempt at a solution I know it's a...
  8. T

    MHB Finding domain of a function with square root in bottom of fraction\infty

    I need to find the domain of this function.$$h(x) = 1 / \sqrt[4]{x^2 - 5x}$$ So, I understand that I need to set $$x^2 -5x > 0$$ from that I get $$ x(x-5) > 0$$ and $$ x > 5$$ However, the answer in the textbook is given: $$ ( \infty, 0) \cup (5, \infty)$$ Which mean that the graph has a...
  9. O

    MHB Solving Square Root Questions: A Math Tutorial for Beginners

    How does this work? (Also, I am very math illiterate and do not understand even the most basic terms, if you could kindly speak as you would to a child I would GREATLY appreciate it.) sq rt sign over 13^2 - 12^2 (over both of it together) Now the answer is 5, because (13)(13) - (12)(12)...
  10. E

    Units square root of a Newton

    I have a table with several quantities in it, and one of them is \sqrt{T} (T is tension) I have values for this table, and want to put the units next to the values. Something seems off to me about doing this, I guess because they're not integers. Is it correct to say the units are kg1/2m1/2s-1...
  11. jnbp13

    Easiest Method to Evaluate Imperfect Square Root up to 5 Decimals?

    Easiest Method to Evaluate Imperfect Square Root up to 5 Decimals? Any ideas?
  12. johann1301

    Proving √2 Irrational - Explanation & Solution

    Homework Statement In this task we will show that √2 is irrational. Assume that √2 = a/b where both a and b are natural numbers. Let a = p1p2p3...pn, and b = q1q2q3...qm be the prime factors a) explain why 2q1q1q2q2q3q3...qmqm = p1p1p2p2p3p3...pnpn √2=a/b b√2=a...
  13. A

    My proof that the square root of 2 multiplied by r is irrational

    Here it is, for you to critique. This is a proof by contradiction. This is a good example of how I usually go about doing proofs, so if you give me tips on how to improve this particular proof, I'll be able to improve all my other proofs. I just learned how to do proof by contradiction...
  14. T

    Vector & Square Root Question for GCSE Maths

    I have attached a copy of a vector question which i cannot do, i do not even understand what the question is asking can someone help? On a different note i seem to have a lot of trouble with simplifying square roots for example what is the square root of 2704/ is there any way to find the...
  15. S

    Binomial series - Finding square root of number problem

    Homework Statement Expand ##(1+x)^(1/3)## in ascending powers of x as far as the term ##x^3##, simplifying the terms as much as possible. By substituting 0.08 for x in your result, obtain an approximate value of the cube root of 5, giving your answer to four places of decimals. Homework...
  16. 1

    Square root of a Mersenne Number is irrational

    Homework Statement A user on math.se wanted to prove that any Mersenne number m = 2^n - 1 has an irrational square root for n > 1. So, it can be proved rather easily that any non-perfect square has an irrational root, and that all of the numbers to be considered are not perfect squares...
  17. Albert1

    MHB Manipulation of square root function

    $\dfrac {\sqrt {3-3x}+\sqrt {x+6}}{\sqrt {1-4x}+\sqrt {2x+8}}=\dfrac {\sqrt {3-3x}-\sqrt {x+6}}{\sqrt {1-4x}-\sqrt {2x+8}}$ please find :$x$
  18. P

    Raising to half power = PRINCIPAL square root?

    This may seem like a very elementary question...but here goes anyway. When a positive number is raised to the power 1/2, I have always assumed that this is defined as the PRINCIPAL (positive) square root, e.g. 7^{1/2} = \sqrt{7},. That is, it does not include both the positive and negative...
  19. N

    Integral involving square root and exp

    Homework Statement \int\frac{dx}{\sqrt{e^{x} + 1}} Homework Equations Using u-substitution The Attempt at a Solution Let u = \sqrt{e^{x} + 1} \Rightarrow u^{2} - 1 = e^{x} Then, du = \frac{e^{x} dx}{2\sqrt{e^{x} + 1}} \Rightarrow dx = \frac{2u du}{u^{2}-1} So...
  20. M

    What is the Constructibility of the Square Root of 2?

    Sorry for any mispellings, English is not my first language. So, I'm studying irrational numbers and I got curious about something and my teacher couldn't give me the answer. I understand Pi must exist because it's the simple result of a division (perimeter by diameter). But how can the...
  21. S

    Algebra and square root simplification

    Homework Statement Points A and B are 10 km apart and it is determined from the sound of an explosion heard at those points at different times that the location of the explosion is 6 km closer to A than B. Show that the location of the explosion is restricted to a particular curve and find...
  22. A

    MHB How to Integrate (x^2 + 2x + 1)sqrt(4x^2 + 8x + 5)?

    how do i integrate (x^2 + 2x + 1)sqrt(4x^2 + 8x + 5)??
  23. F

    Complex Square Root Analyticity

    Homework Statement Let f(z) denote the multivalued function (z^{2} − 1)^{1/2} . Define a branch of f(z) which is analytic in the interior of the unit disk |z| < 1 2. The attempt at a solution Having a bit of trouble getting started. I have rewritten f(z) as ((z-1)(z+1))^{1/2} as...
  24. C

    Proof that the Square Root of 2 is Irrational.

    I am trying to prove that √2 is irrational using proof by contradiction. Here is my work so far: √2 = p/q where p & q are in their lowest terms. Where q is non-zero. 2=p2/q2 2q2 = p2 Which tells me that p2 is an even number, using the definition of an even number. We can use this definition...
  25. anemone

    MHB Compute a square root of a sum of two numbers

    Compute $\sqrt{2000(2007)(2008)(2015)+784}$ without the help of calculator.
  26. I

    Integrating a Square Root Function: Solution

    Homework Statement ∫(0,1) √x/√[3]1-x Homework Equations \Gammap\Gammaq/\Gammap+q The Attempt at a Solution p-1=1/2 →p=3/2 q-1=-1/3 →q=2/3 β(3/2,2/3)=\Gamma(3/2) \Gamma(2/3)/\Gamma(13/6) \Gamma3/2=1/2\Gamma(1/2)=√π/2 \Gamma2/3=-1/3 \Gamma13/6=7/6 1/6=7/36 β(3/2,2/3)=-6√π/7
  27. kini.Amith

    What is the Value of √i + √-i?

    Homework Statement The value of √i + √-i , where i=√-1 is (a) 0 (b) 1/√2 (c) √2 (d) -√2 Only one option can be chosen Homework Equations The Attempt at a Solution Let (x + iy)2=i Solving for x and y, I got √i = +1/√2 (1+i) or -1/√2...
  28. A

    Finding the power series of a square root

    Homework Statement Find a power series for f(x) = \frac{1}{\sqrt{4+x^{2}}}, at x=0. 2. The attempt at a solution I have looked up the Taylor series of \frac{1}{\sqrt{4+x^{2}}}, but I don't find any similarity with a power serie like \sum_{n\geq 0} a_{n} x^{n} I don't know how to start...
  29. A

    Defining the square root of an unbounded linear operator

    I have started coming across square roots (H+kI)^{\frac 12} of slight modifications of Schrodinger operators H on L^2(\mathbb R^d); that is, operators that look like this: H = -\Delta + V(x), where \Delta is the d-dimensional Laplacian and V corresponds to multiplication by some function. But...
  30. H

    What is the limit of a function under a square root?

    Homework Statement lim x-> 2+ f(x)=sqrt(4-x^2)whats the value of the following function?? Homework Equations The Attempt at a Solution i tried and got the answer as does not exist but some people got it as 0 which is the correct answer
  31. K

    If p is prime, then its square root is irrational

    Homework Statement Im trying to prove that if p is prime, then its square root is irrational. The Attempt at a Solution Is a proof by contradiction a good way to do this? All i can think of is suppose p is prime and √p is a/b, p= (a^2)/ (b^2) Is there any property i can...
  32. N

    Integral: square root of sum of trig polynomials

    Hi, I am trying to make progress on the following integral I = \int_0^{2\pi} \sqrt{(1+\sum_{n=1}^N \alpha_n e^{-inx})(1+\sum_{n=1}^N \alpha_n^* e^{inx})} \ dx where * denotes complex conjugate and the Fourier coefficients \alpha_n are constant complex coefficients, and unspecified...
  33. A

    MHB Square Root Rules for Fractions: x∈[3,∞)

    \sqrt{\frac{x-3}{x}} = \frac{\sqrt{x-3}}{\sqrt{x}} that is not true for all x, it is true for x\in [3,\infty) I want to teach my students that the exponents distribute over fractions unless we have a case like that square root or any even root. what do you think ?
  34. S

    Rationalizing the denominator involving more than one square root

    Here's my problems: How might you "rationalize the denominator" if the expression is \frac{1}{2+7√2+5√3} or \frac{1}{\sqrt[3]{2}+1}? I know that in typical problems where we rationalize the denominator, we simply have to multiply the denominator and numerator by the conjugate of the denominator...
  35. R

    An Integral With A Square Root In The Denominator

    How would you integrate it? \int \frac{d \varphi}{\sqrt{1 + \frac{a^2 b^2 \sin^2 \alpha}{(a \sin \varphi + b \sin (\alpha - \varphi))^2}}} I know that solving it numerically would probably be easier, but I would prefer a closed form solution in this case.
  36. A

    Solving for "a" in Square Root Equation

    Homework Statement Get the value of a if \sqrt{6-\sqrt{a}}+\sqrt{6+\sqrt{a}}=\sqrt{14} The Attempt at a Solution nothing succesfull Feel free to move this thread,..I actually place it here to tap more brains
  37. V

    Formula & Conversion with a square root

    I'm comparing the shear formula for a beam in english and metric. But it seems the formula or result don't match. In English, the formula is Vc=2*b*d*sqrt(Fc) Given b=11.81102 inches d=18.11024 inches fc=4000 psi Vc=2*b*d*sqrt(Fc)=27056 lbs Now converting the units in metric...
  38. Petrus

    MHB Integrate Sine and Square root Composite Function

    Hello MHB, I got stuck on integrate this function \int \frac{\sin^3(\sqrt{x})}{\sqrt{x}}dx my first thinking was rewrite it as \int \frac{\sin^2(\sqrt{x})\sin(\sqrt{x})}{\sqrt{x}}dx then use the identity \cos^2(x)+\sin^2(x)=1 \ \therefore \sin^2x=1- \cos^2(x) \int...
  39. Barioth

    MHB How to Solve These Challenging Integrals with Square Roots?

    Hi everyone I have these 2 integrate that I can't solve, I have tried them with mathematica and wolfram, but they can't find an answer, maybe someone have an idea on how I could tackle these 2 bad boy! The first one is \int{ \sqrt{ \frac{1+( \frac{1}{10}+ \frac{s}{25})^2}{ \frac {s}{10}+...
  40. O

    My Taylor Square Root C Program doesn't like me

    Homework Statement 4. Implement a simple method to find the square root of a double precision floating point number x. A simple method is to consider the error produced by a “guess” y of the solution. Square the value y and compare with the value x. If y is correct, the error e=|y2-x| where ||...
  41. G

    Is Taking the Principal Square Root Always Necessary?

    I feel kind of ridiculous making this post, but here we go: What would be the correct answer to this question; Choose all the number sets (natural, integer, rational, or irrational were the only options given) that -√81 belongs to, and show how you found your answer. What I said was this...
  42. S

    Square Root of Positive Operator

    Homework Statement Suppose U = T^2 + \alpha T + \beta I is a positive operator on a real inner product space V with \alpha^2 < 4 \beta . Find the square root operator S of U.Homework Equations The Attempt at a Solution Isn't this just the operator S \in L(V) such that S e_k = \sqrt{...
  43. M

    How Do You Find The Exact Value Of Square Root of 3, 5, 7, 11?

    Is there any method to find the exact value of the square root of 3,5,7,11,13,14,15,17,18, etc.? Thank you
  44. C

    Integral of 1 - 2*sinx in square root?

    Hello PF members, I want to solve this integral but I cannot find a method. \int\sqrt{1 - 2sin(x)}dx for 0 < x < ∏/6 Or more generally \int\sqrt{a - bsin(x)}dx for a > b How can I solve this? Thanks in advance
  45. B

    Square Root Indefinite Integral

    Hello everyone.. Homework Statement ∫√((1+(e^-x))^2)dx 2. The attempt at a solution I first tried to do a u sub and then attempt a trig sub however I can't do anything with the e^-x left in the u sub. Does anyone have another way I can integrate this thing?? Thank you for any suggestions/help!
  46. R

    Let G be a finite group in which every element has a square root

    Homework Statement Let G be a finite group in which every element has a square root. That is, for each x in G, there exists a y in G such that y^2=x. Prove every element in G has a unique square root. Homework Equations G being a group means it is a set with operation * satisfying...
  47. L

    Integration by parts involving square root

    Homework Statement |x3sqrt(4-x2)dx Homework Equations uv - | vdu The Attempt at a Solution u = x2 v = -1/3(4-x2)3/2 du = -2xdx dv = x(4-x2)1/2 uv - | vdu x2(1/3)(4-x2)3/2 - | 1/3(4-x2)3/2(2xdx) x2(1/3)(4-x2)3/2 +(1/3)|(4-x2)3/2(2xdx) u = 4 - x2 du = -2xdx...
  48. X

    Log base 2 is the same thing as square root?

    Hi, Is is correct to say that the logarithm of base 2 of a number x, is the same thing as the square root of a number x?
  49. G

    Square root of a squared block matrix

    Hi everybody, I’m trying to compute the square root of the following squared block matrix: \begin{equation} M=\begin{bmatrix} A &B\\ C &D\\ \end{bmatrix} \end{equation} (that is M^(1/2))as function of A,B,C, D which are all square matrices. Can you help me? I sincerely...
  50. B

    Proof of square root 3 irrational using well ordering

    The part I don't understand is how they show there exists a smaller element. They assume s=t√3 is the smallest element of S={a=b√3: a,b€Z} . Then what they do is add s√3 to both sides and get s√3-s=s√3-t√3. I don't get how they thought of that or why it works.I know there exists an element...
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