Trigonometry Examples

$\arccos (x) = \arcsin (\frac{7}{25})$

Step 1

Take the inverse arccosine of both sides of the equation to extract $x$ from inside the arccosine.

$x = \cos (\arcsin (\frac{7}{25}))$

Step 2

Simplify the right side.

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Step 2.1

Simplify $\cos (\arcsin (\frac{7}{25}))$ .

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Step 2.1.1

Draw a triangle in the plane with vertices $(\sqrt{1^{2} - {(\frac{7}{25})}^{2}}, \frac{7}{25})$ , $(\sqrt{1^{2} - {(\frac{7}{25})}^{2}}, 0)$ , and the origin. Then $\arcsin (\frac{7}{25})$ is the angle between the positive x-axis and the ray beginning at the origin and passing through $(\sqrt{1^{2} - {(\frac{7}{25})}^{2}}, \frac{7}{25})$ . Therefore, $\cos (\arcsin (\frac{7}{25}))$ is $\sqrt{\frac{576}{625}}$ .

$x = \sqrt{\frac{576}{625}}$

Step 2.1.2

Rewrite $\sqrt{\frac{576}{625}}$ as $\frac{\sqrt{576}}{\sqrt{625}}$ .

$x = \frac{\sqrt{576}}{\sqrt{625}}$

Step 2.1.3

Simplify the numerator.

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Step 2.1.3.1

Rewrite $576$ as $24^{2}$ .

$x = \frac{\sqrt{24^{2}}}{\sqrt{625}}$

Step 2.1.3.2

Pull terms out from under the radical, assuming positive real numbers.

$x = \frac{24}{\sqrt{625}}$

Step 2.1.4

Simplify the denominator.

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Step 2.1.4.1

Rewrite $625$ as $25^{2}$ .

$x = \frac{24}{\sqrt{25^{2}}}$

Step 2.1.4.2

Pull terms out from under the radical, assuming positive real numbers.

$x = \frac{24}{25}$

Step 3

The result can be shown in multiple forms.

Exact Form:

$x = \frac{24}{25}$

Decimal Form:

$x = 0.96$