Trigonometry Examples

$\cos (\frac{π}{2} - x) \cos (- x) = \frac{\sin (2 x)}{2}$

Step 1

Since $\cos (- x)$ is an even function, rewrite $\cos (- x)$ as $\cos (x)$ .

$\cos (\frac{π}{2} - x) \cos (x) = \frac{\sin (2 x)}{2}$

Step 2

Graph each side of the equation. The solution is the x-value of the point of intersection.

$x \approx 0, 0.1, - \frac{1}{5}, \frac{1}{5}, 0.3, - \frac{2}{5}, - \frac{1}{2}$

Step 3

The result can be shown in multiple forms.

Exact Form:

$x \approx 0, 0.1, - \frac{1}{5}, \frac{1}{5}, 0.3, - \frac{2}{5}, - \frac{1}{2}$

Decimal Form:

$x \approx 0, 0.1, - 0.2, 0.2, 0.3, - 0.4, - 0.5$

Step 4