Solveeit Logo
Login

Question

Mathematics Question on Inverse Trigonometric Functions

cos⁡−1(5−14)=\cos^{-1} ( \frac{\sqrt{5} -1}{4} ) =

A

3π10\frac{3 \pi}{10}

B

2π5\frac{2 \pi}{5}

C

π5\frac{ \pi}{5}

D

π15\frac{\pi}{15}

Answer

2π5\frac{2 \pi}{5}

Explanation

Solution

5−14=cos⁡72∘\frac{\sqrt{5} -1}{4} = \cos 72^{\circ}