Proof of \sqrt{ab} = \sqrt{a}\sqrt{b} for all ab>0

You could use induction on one of them, but you'd still need something else to get from P(n) to P(n+1).In summary, the conversation discusses whether the equation \sqrt{ab} = \sqrt{a}\sqrt{b} holds true for all real and nonnegative numbers a and b. The method of induction is suggested, but it is determined that it is not applicable in this case.
  • #1
annoymage
362
0

Homework Statement



[tex]\sqrt{ab}[/tex] = [tex]\sqrt{a}[/tex][tex]\sqrt{b}[/tex] for all ab>0

Homework Equations





The Attempt at a Solution



let a=0, [tex]\sqrt{0}[/tex] = [tex]\sqrt{0}[/tex]

assume that it's true for some a, consider a+1

[tex]\sqrt{(a+1)b}[/tex] = and I'm lost
 
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  • #2
annoymage said:

Homework Statement



[tex]\sqrt{ab}[/tex] = [tex]\sqrt{a}[/tex][tex]\sqrt{b}[/tex] for all ab>0

Homework Equations





The Attempt at a Solution



let a=0, [tex]\sqrt{0}[/tex] = [tex]\sqrt{0}[/tex]

assume that it's true for some a, consider a+1

[tex]\sqrt{(a+1)b}[/tex] = and I'm lost

Why do you think that this should be done by induction?
 
  • #3
ooops, yea, on second thought, induction is for integer, not real numbers

is there any ways to proof this?
 
  • #4
but wait,

[tex]\sqrt{ab}[/tex] = [tex]\sqrt{a}[/tex][tex]\sqrt{b}[/tex] for all integer a and b such that ab>0

how about that? can i solve this using induction?
 
  • #5
How is the problem stated? Does it explicitly specify that a and b are integers? Also, does it say ab > 0 or does it say a > 0 and b > 0? There's a difference.
 
  • #6
Mark44 said:
How is the problem stated? Does it explicitly specify that a and b are integers? Also, does it say ab > 0 or does it say a > 0 and b > 0? There's a difference.

no, i just made one up.

but what about

[tex]\sqrt{ab}[/tex] = [tex]\sqrt{a}[/tex][tex]\sqrt{b}[/tex] for all integer a and b such that ab>0

can't i prove it using induction?
 
  • #7
Induction really isn't a good fit here. With an induction proof you have a sequence of statements P(1), P(2), P(3), ..., P(n), ... With the problem you made up, you have two variables a and b, both of which should be real and nonnegative.
 

FAQ: Proof of \sqrt{ab} = \sqrt{a}\sqrt{b} for all ab>0

What does "Proof of √(ab) = √a√b for all ab>0" mean?

This statement is a mathematical equation that asserts that the square root of the product of two positive numbers (a and b) is equal to the product of their individual square roots. In other words, when we multiply two positive numbers and take the square root of the result, it is the same as taking the square root of each number separately and then multiplying them together.

Why is this proof important?

This proof is important because it is a fundamental property of square roots and plays a crucial role in many mathematical calculations and applications. It also helps us understand the relationship between multiplication and square roots, which is essential in higher-level mathematics.

How can we prove this statement?

This statement can be proven using algebraic manipulation and the properties of exponents. By using the distributive property and simplifying the resulting equations, we can show that the two sides of the equation are equal.

Does this statement hold true for all positive numbers, or are there any exceptions?

This statement holds true for all positive numbers, as long as a and b are both greater than 0. If either a or b is negative, the equation is not valid.

Can this statement be extended to other operations, such as division or powers?

Yes, this statement can be extended to other operations, such as division and powers. For example, we can prove that √(a/b) = √a/√b and (√a)^n = √(a^n) for all positive numbers a and b, and any integer n. However, this proof is specific to the square root operation and cannot be applied to other types of roots, such as cube roots or fourth roots.

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