Sin Definition and 452 Threads

  1. Q

    Solve for d: "Finding Unknowns in Equations with Sin and Cos

    Homework Statement I have this equation, but I'm having trouble solving for the unknown :/ I know that d is 109; I just don't know how to get it. see below Homework Equations -dsin35 = -4.9(dcos35/25)^2 The Attempt at a Solution -dsin35 = -4.9d^2 cos^2(35)/25^2 -dsin35 = -4.9d^2 cos(35) x...
  2. R

    Sum of (-1)^(k+1) * sin (kx)/k

    Homework Statement In short, I want to find \sum^{\infty}_{k=1} (-1)^{k+1} sin(kx)/k I happen to know(/strongly believe) this is equal to x/2, but I'm not sure how to show it. If we could show that sum k=1 to infinity of (-e^2pi i x/p )^k=-e^(2pi i x/p)/(1+e^(2pi i x/p)) that would suffice (...
  3. F

    Instantaneous velocity and cos, sin

    I'd like to apologize for not using the symbols but I spent over 1 1/2 hours trying and after using one of the symbols it wouldn't format correctly for any others. The s^2. s^3 etc... are seconds Homework Statement A particle is moving in one-dimension, and its acceleration in m/s^{2}as...
  4. C

    Y= l sin x l < absolute value of sinx

    Homework Statement y= l sin x l < absolute value of sinx Homework Equations The Attempt at a Solution y= l sin x l= sinx, if x>0 -sinx, if x< 0 0, if x=0 I get that part, but when i draw the graph I don't get it
  5. M

    What is the Integral of x^2 sin pi x?

    My calc is a bit rusty & i can not solve this problem for the life of me. its the integral of x^2sin pi x. I know you must integrate by parts..& i am have tried using both x^2 and sin pi x as my u. Any help? time is of the essence.
  6. J

    Graphing sin and cos functions

    Homework Statement plot x(t) = 10cos((pi*t)-(pi/4)) Homework Equations pi/4 is the shift to the right 10 is the amplitude of the graph pi is the radian frequency The Attempt at a Solution so i got the amplitude and shift to the right by pi/4 part but as for the radian...
  7. T

    SOlving y-intercept of a sin function

    Homework Statement y = -2sin2(x+[pi/6])+1 for x [-pi, pi] The Attempt at a Solution set y=0, 1/2 = sin2(x+[pi/6]) pi/6 = 2(x+[pi/6]), where pi/6 is the base angle Now because of the 2 infront of the (x+[pi/6]), I consider twice the domain, i.e. [-2pi, 2pi]. pi/6 is positive...
  8. A

    Is the time average of a sin function = 0?

    Hello all. I just have a simple question. Suppose a classical charged particle is interacting with a potential of the form V(t) = V Sin(wt). The interaction energy is qV(t). My question is, will the time-average of this interaction be zero? Could someone please show me an equation of how to get...
  9. Z

    Can Complex Numbers Rotate and Invert Sine Functions?

    Sry, noob, but i didn't find this anywhere.
  10. stripes

    Proving Int. of Even Powers of Sin

    Homework Statement should be my last question for at least the next few days...here goes... Prove that, for even powers of sine, \int^{\frac{\pi}{2}}_{0}sin^{2n}x dx = \frac{2\cdot4\cdot6\cdot...\cdot(2n - 1)}{2\cdot4\cdot6\cdot...\cdot2n}\cdot\frac{\pi}{2}Homework Equations uv - \int v du...
  11. C

    Comp Sci Plotting sin x on an XY Plane with C++

    Homework Statement Hi, I'm writing a c++ code which is about making an xy plane with dots and then using an array an plot a math function with a character. the functions i need to plot are sin x, sqrt x and a polynomial. so far I attempted to make a function for plotting sin x, but I always get...
  12. F

    Why Do Cosine and Sine Waves Have Different Fourier Transforms?

    Hi, if cosine and sine waves are exactly the same wave except cosine starts earlier in time, why do they have different Fourier Transforms? I know the cos would have an impulse at f=Fc with amplitude of 1, and sin would have an impulse at f=Fc and amplitude of 1/j. I don't understand why the...
  13. L

    Use '3 sin x - 4(sin x)^3' to show that if sin x = sin (3x), then sin x = 0 or

    Use '3 sin x - 4(sin x)^3' to show that if sin x = sin (3x), then sin x = 0 or... Homework Statement Use double-angle and addition formulæ and other relations for trigonometrical functions to find an expression for sin(3x) in terms of sin x alone. Use the expression you have found to show...
  14. L

    Finding an expression for (e.g. sin (3x)) in terms of (e.g. sin x) alone?

    Homework Statement Use double-angle and addition formulæ and other relations for trigonometrical functions to find an expression for sin(3x) in terms of sin x alone. My problem is I don't know what is meant by "find an expression for sin(3x) in terms of sin x alone.". I know the relevant...
  15. H

    Solving equations in sin and cos theta

    Hi, I have been trying to solve some mechanics problems and I can come up with the right equation, but I don't know how to solve it... For example: 490.5cos(theta) - 3600cos(theta)sin(theta) + 1800sin(theta) = 0 i need to solve for theta here its one equation and one unknown...
  16. B

    Does anyone know how to find radius of convergence for sin x and e^x

    [sloved]Does anyone know how to find radius of convergence for sin x and e^x We know that to find radius of convergence we use ratio test (ie lim {a_n+1} /{a_n}) Can this method be used for sin x and e^x? ( whose radius of convergence is -infinity and infinity) if radius of convergence is...
  17. S

    How Far Beyond the Fence Does the Ball Land?

    A kid is 5 m from a fence that is 4 m high. He throws a ball at 45° from the horizontal which just grazes the fence. How far beyond the fence does the ball land? You may assume that the ball was thrown from the same level as the ground on the far side of the fence. Here's how i did it and its...
  18. S

    Discovering the Exact Value of sin45: A Trigonometry Homework Guide

    Homework Statement Which of the following is the exact value for sin45?? Homework Equations a) 2/(sqrt 2) b) (sqrt 2)/2 c) 1/(sqrt 2) d) (sqrt 3)/2 e) sqrt 2 The Attempt at a Solution I have no idea how to work out exact values for trig functions??
  19. T

    Definitite integrals involving sin and cos.

    Hi! I have learned how to solve equations like: \int^{2\pi}_{0}\frac{1}{1+sin\theta}d\theta using \int^{2\pi}_{0}F(sin\theta,cos\theta) d\theta \int_{C}F(\frac{z-z^{-1}}{2i},\frac{z+z^{-1}}{2}) \frac{dz}{iz} How do I solve equations of the type...
  20. A

    Integration by Parts with sin and ln(x)

    Homework Statement The method to use to integrate the function is up to us. The choices are: 1) U-substitution 2)Integration by Parts 3)Trigonometric integrals 4)Trigonometric substitution 5)Partial fraction Homework Equations According to me, the best way to do it is to use...
  21. G

    Solving Sin theta Questions: An Example

    Homework Statement sorry if the title is not that descriptive Homework Equations i is the imaginary number e is 2.7... x is any anlgle in radians that is... um see the example I explain it sin x = +/- i/2 (1/e^(ix) +/- e^(ix)) I will use a example in atempt at a solution to show...
  22. G

    Where Can I Find a Table of Exact Values for sin(theta)?

    Homework Statement Does anyone know were I can find a table on the internet of the exact values of sin theta were theta is any whole angle from zero to ninety degrees Example sin 0 degrees sin 1 degrees sin 2 sin 3 sin 4 sin 5 ... sin 90 Homework Equations The Attempt at...
  23. R

    Find values of sin, cos, tan, sec, csc, and cot without a calculator

    Homework Statement I'm wondering how you would find values of sin, cos, tan, sec, csc, and cot without a calculator. I don't have a specific problem but how would you solve things like tan 45 degrees, sec 30 degrees, and cos -30 degrees? 2. Relevant info I have the values of sin and...
  24. K

    Continuous random variable - transformation using sin

    Homework Statement There is a pin of length 4 which appear on a photograph, and the length of the image observed is y, an observation on the random variable Y. The pin is at an angle x, 0\leqx\leq\pi/2, to the normal to the film, this is an observation on the r.v. X. 1. If all angles X...
  25. O

    Bifurcation diagram of a sin map(plotting it)

    Homework Statement Make a bifurcation diagram for the sin map x{sub t+1} = f(x{sub t}) where f(x) = rsin(pi*x). Homework Equations The Attempt at a Solution A bifurcation diagram... I have read and understood what a bifurcation diagram is, and how it is constructed, but to...
  26. O

    Sin Wave Generator IC: Find Availability in Your Country

    can anyone please give me aname of sin wave generator IC .but many ICS as you know as it might be not available in my country
  27. K

    Area of y = sin x is equal to y = x^2, find k

    Homework Statement If the area under y = sin x is equal to the area under y = x^2 between x = 0 and x = k, then k = : Homework Equations The Attempt at a Solution I do not have any idea how to do this problem. So I asked my friends for help, but their methods are different. One of...
  28. Z

    Sin i / sin r graph from ray through glass block

    Homework Statement I have done the light ray through a glass block experiment at different angles. I've taken the measurement for i1 which is from the incident ray. and i2 which is from the emergent ray. Then I have to take the average of i1 and i2 and then plot a graph using the average...
  29. 0

    Ξ cm = 4.9 sin (1.06 x - 0.77 t) - Determine Travelling Speed of Wave

    Homework Statement The equation of a wave along the x-axis is given as: ξ cm = 4.9 sin (1.06 x - 0.77 t) in which ξ is the displacement. Units on the right hand side are 1/cm for К and 1/s for ω. Determine the the traveling speed of the wave. Express the result in the unit m/s and to...
  30. J

    Using Rolle's Theorem to Find Extremes of f(x) = sin 2x

    Homework Statement I need to use Rolle's theorem to find analitically the maxium and the minimun extremes on the interval [0 , 1/2pi] . So I think I must first find the derivative of the fuction and to solve for x the function given is f(x) = sin 2x Homework Equations...
  31. D

    How can F = mg sin. θ be proven on a smooth plane?

    i can't understand the formula F = mg sin. θ on a smooth plane how to proof a = g sin. θ sin. θ... http://img213.imageshack.us/img213/2313/44877072.jpg
  32. J

    How Do I Choose Between Sin, Cos, and Tan in Trigonometry Problems?

    No problem specifically, just more of a method question. I am extremely confused on when to use sin cos and tan. Say for instance it gives me an angle, say theta, and one side. How would I be able to tell what to use sin cos or tan. I know the trick SohCahToa but I really am confused. I am in a...
  33. J

    When and how do I use sin and cos regarding 2-D collisions?

    I think what I'm doing is overkill because all I want to know is when to use sin and cos in the components regarding (isolated) two-dimensional collisions. I'm just showing more content because it might help for context. Also, there are more steps in order to find the final velocity which is...
  34. C

    Converting a sin regression to cos regression

    Homework Statement convert a*sin(bx+c)+d to (mx+d)+a*cosb(x-c) Homework Equations The Attempt at a Solution
  35. P

    Sin(pi/2) (different from sin )

    sin(pi/2) (different from sin!) how can sin(pi/2) be equal to 1 , i mean sinx is defined as the ratio P/H of a right triangle , but if sinx = 1 => P=H , but by Phytogoras => B=0 , but how is this possible ? so how can sinx =1 exist?
  36. R

    Newton Applications. Help solving equation with sin and cos.

    Homework Statement At an airport, you pull a 18-kg suitcase across the floor with a strap that is at 45 degrees above the horizontal. Find the normal force and the tension on the strap, given that the suitcase moves with a constant speed and the coefficient of kinetic friction is 0.38...
  37. tony873004

    Can AC sin (B/C) = B be Analytically Solved?

    Where A and C are constants. Is there any analytic to solve for B?
  38. M

    Trig question eq in the form y = sin k x

    Homework Statement http://img62.imageshack.us/img62/7677/30639229.jpg Homework Equations y = sin k x The Attempt at a Solution Looking for help with part 12b in particular so i can try 13c Im not quite sure how the coefficent of x (K) in the function y=sin kx relate to...
  39. S

    Sin -270 different from sin - 90 exact and aprox values?

    Homework Statement Homework related question:Write the exact value of sin(-270) The Attempt at a Solution I had this same question before but to write it in approximate value. for an aprox value i simply just plug it into my calculator and get: 1. Pretty exact for an approximate value...
  40. D

    Deriving Σ sin n using Euler's formula

    Homework Statement I was looking over my notes and there was a part that didn't make sense. It's basically using the Euler's formula (e^{ix}=cos(x)+isin(x)) and the fact that sin(x)=Im(e^{ix}) to find what Σ sin n sums to. It starts out like this: But this part isn't relevant to my...
  41. J

    Solve sin cos: Find cos6x - 4cos4x + 8cos2x =?

    Can anyone give any hint to solve this ? If sinx + sin2x + sin3x = 1, then , cos6x - 4cos4x + 8cos2x = (a) 1 (b) 4 (c) 2 (d) 3
  42. G

    Show that arcsin is the inverse of sin

    Homework Statement I have a problem, I don't know to substantiate, why arcsin(sin(x)) = sin(arcsin(x)) = x ? Thank you very much for each advice. Homework Equations The Attempt at a Solution
  43. P

    Solving the Wave Equation with D=A sin kx cos \omegat

    [b]1. Homework Statement [/b Determine whether the function D=A sin kx cos \omegat is a solution of the wave equation. Homework Equations D=Asin (kx-\omegat) The Attempt at a Solution sorry completely lost please help
  44. G

    Simple linear transformation of coordinates on a sin wave

    Homework Statement let x=ksin(t). let k<1. let x'=x. let t'=t-kx. solve for x' as a function of t'. (this question has to do with relativity and deBroglie waves)Homework Equations given above.The Attempt at a Solution since t=t'+kx therefore x'=ksin(t'+kx). but I need x' as a function of t'...
  45. Somefantastik

    Are these the correct cos and sin relations for the given values?

    if \mu = cos(\theta) and \mu_{0} = cos(\theta_{0}) and cos(\pi - \Theta) = \mu_{0}\mu + \sqrt{1-\mu_{0}^{2}}\sqrt{1-\mu^{2}}cos(\phi) Then cos(\pi - \Theta) = cos(\theta_{0})cos(\theta) + sin(\theta_{0})sin(\theta)cos(\phi) Is this not correct?
  46. E

    Integration - two sin functions

    Homework Statement I have the answer I just don't know how he got it! I want to know how he got from the second line to the third line in the image below. Homework Equations The Attempt at a Solution I have used integration by part and the u substitution method. When...
  47. O

    Can WolframAlpha help me find the sin (cos x) or cos (sin x)?

    Hi everyone, Can someone please tell me how the method I can find the sin (cos x) or cos (sin x)? Thanks in advance Huygen
  48. S

    Prove that sin x < x for x > 0

    Anyone knows how to prove it using Taylor's theorem?
  49. P

    Writing sin^2 theta * Sin 2 phi in terms of spherical Harmonics

    I am trying to write the term "Sin^2 theta * Sin 2 phi" in terms of spherical Harmonics (they form a combination of Y(2,-2) and Y(2,2)) but the term I get contains the imaginary number 'i'. Am I doing something wrong.. In fact this term is a part of a Hamiltonian and when I get the eigenvalues I...
  50. H

    Does lim x →0 sin 1/x exist? also .

    Does lim x →0 sin 1/x exist? also... Homework Statement does lim x →0 sin(1/x) exist? The Attempt at a Solution I am very new to calculus. From what i have understood till now, limit of a function at a point exists only if the left and right hand limits are equal. What would the...
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