Last modified on November 19th, 2024

chapter outline

 

Exponents and Square Roots

Exponents and square roots are inversely related operations. While exponents involve raising a number to a power, square roots inverse this operation by finding the original base that, when squared, gives the result.

For example, 

8 to the 2nd power is 82 = 64, which means 8 is multiplied by itself 2 times. When exponents are used, the results grow very rapidly. 

Now, to find the square root of 64, we need a number that, when squared (multiplied by itself), equals 64. That number is 8, so the square root of 64 is 8. 

Exponents to Square Roots

When converting an exponent into a square root, the base, say x, is raised to the fractional exponent, ${x^{\dfrac{1}{2}}}$, which represents the square root of that base. It can be expressed as 

${x^{\dfrac{1}{2}}=\sqrt{x}}$

In general, raising a base to the power of ${\dfrac{1}{n}}$ corresponds to finding the nth root of the base.

For example,

${9^{\dfrac{1}{2}}=\sqrt{9}=3}$

Square Roots to Exponents

To express a square root as an exponent, the base under the radical is rewritten with a fractional exponent. It is expressed as 

${\sqrt{x}=x^{\dfrac{1}{2}}}$

More generally, an nth root is written using a fractional exponent: ${\sqrt[n] {x}=x^{\dfrac{1}{n}}}$

For example,

${\sqrt{9}=9^{\dfrac{1}{2}}}$

However, to simplify complex problems involving these conversions, we need to follow certain rules.

Rules

Here are the rules for simplifying expressions involving both square roots and exponents.

Exponents in Square Roots

Solved Examples

Simplify: ${\sqrt{x^{4}}}$

Solution:

Here, ${\sqrt{x^{4}}}$
Converting the square root into an exponent,
${x^{\dfrac{4}{2}}}$
= x2 
Thus, ${\sqrt{x^{4}}}$ = x2

Simplify: ${\sqrt{16x^{6}}}$

Solution:

Here, ${\sqrt{16x^{6}}}$
Using the product rule for radicals,
${\sqrt{16}\times \sqrt{x^{6}}}$
= ${4x^{\dfrac{6}{2}}}$
= ${4x^{3}}$
Thus, ${\sqrt{16x^{6}}}$ = ${4x^{3}}$

Solve: ${\dfrac{\sqrt{x^{5}}}{\sqrt{x^{2}}}}$

Solution:

Here, ${\dfrac{\sqrt{x^{5}}}{\sqrt{x^{2}}}}$
Using the quotient rule for square roots,
${\sqrt{\dfrac{x^{5}}{x^{2}}}}$
= ${\sqrt{x^{5-2}}}$
= ${\sqrt{x^{3}}}$
= ${x^{\dfrac{3}{2}}}$
Thus, ${\dfrac{\sqrt{x^{5}}}{\sqrt{x^{2}}}}$ = ${x^{\dfrac{3}{2}}}$

Simplify the expression: ${\left( \sqrt{x^{6}}\right) ^{2}}$

Solution:

Here, ${\left( \sqrt{x^{6}}\right) ^{2}}$
Using the power of a root rule,
= ${\left( \left( x^{6}\right) ^{\dfrac{1}{2}}\right) ^{2}}$
= ${\left( x^{\dfrac{6}{2}}\right) ^{2}}$
= ${\left( x^{3}\right) ^{2}}$
= ${x^{3\times 2}}$
= ${x^{6}}$
Thus, ${\left( \sqrt{x^{6}}\right) ^{2}}$ = ${x^{6}}$

Last modified on November 19th, 2024