Multiply Square Roots: Solving √8 × √8

Question

Solve the following exercise:

88= \sqrt{8}\cdot\sqrt{8}=

Video Solution

Solution Steps

00:00 Solve
00:03 The square root of a number (A) times the square root of another number (B)
00:07 equals the square root of their product (A times B)
00:11 Let's use this formula in our exercise and calculate the product
00:14 Any number times itself is actually squared, a square root cancels a square
00:17 And this is the solution to the question

Step-by-Step Solution

In order to simplify the given expression, we will use two laws of exponents:

a. The definition of root as an exponent:

an=a1n \sqrt[n]{a}=a^{\frac{1}{n}} b. The law of exponents for power of a power:

(am)n=amn (a^m)^n=a^{m\cdot n}

Let's start by converting the square roots to exponents using the law mentioned in a.:

88=812812= \sqrt{8}\cdot\sqrt{8}= \\ \downarrow\\ 8^{\frac{1}{2}}\cdot8^{\frac{1}{2}}= Let's continue, notice that we got a number multiplied by itself, therefore, according to the definition of exponents we can write the expression we got as a power of that same number, then - we'll use the law of exponents mentioned in b. and perform the exponentiation on the term in parentheses:

812812=(812)2=8122=81=8 8^{\frac{1}{2}}\cdot8^{\frac{1}{2}}= \\ (8^{\frac{1}{2}})^2=\\ 8^{\frac{1}{2}\cdot2}=\\ 8^1=\\ \boxed{8} Therefore, the correct answer is answer c.

Answer

8 8