Precalculus Examples

$x = 4 \cos^{2} (\frac{π}{4})$

Step 1

The exact value of $\cos (\frac{π}{4})$ is $\frac{\sqrt{2}}{2}$ .

$x = 4 {(\frac{\sqrt{2}}{2})}^{2}$

Step 2

Apply the product rule to $\frac{\sqrt{2}}{2}$ .

$x = 4 \frac{{\sqrt{2}}^{2}}{2^{2}}$

Step 3

Rewrite ${\sqrt{2}}^{2}$ as $2$ .

Tap for more steps...

Step 3.1

Use $\sqrt[n]{a^{x}} = a^{\frac{x}{n}}$ to rewrite $\sqrt{2}$ as $2^{\frac{1}{2}}$ .

$x = 4 \frac{{(2^{\frac{1}{2}})}^{2}}{2^{2}}$

Step 3.2

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

$x = 4 \frac{2^{\frac{1}{2} \cdot 2}}{2^{2}}$

Step 3.3

Combine $\frac{1}{2}$ and $2$ .

$x = 4 \frac{2^{\frac{2}{2}}}{2^{2}}$

Step 3.4

Cancel the common factor of $2$ .

Tap for more steps...

Step 3.4.1

Cancel the common factor.

$x = 4 \frac{2^{\frac{2}{2}}}{2^{2}}$

Step 3.4.2

Rewrite the expression.

$x = 4 \frac{2^{1}}{2^{2}}$

Step 3.5

Evaluate the exponent.

$x = 4 \frac{2}{2^{2}}$

Step 4

Raise $2$ to the power of $2$ .

$x = 4 (\frac{2}{4})$

Step 5

Cancel the common factor of $4$ .

Tap for more steps...

Step 5.1

Cancel the common factor.

$x = 4 (\frac{2}{4})$

Step 5.2

Rewrite the expression.

$x = 2$