Question

If cos theta= √3÷2 then find the value of 4cos^3 theta-3 cos theta​

Answer 1

Step-by-step explanation:

Cos theta = √3/2 = Cos30°

then , theta = 30°

4Cos³theta - 3Cos theta = Cos3O

Cos3O = Cos(3*30°)

= Cos90° = 0

Answer 2

$cos\theta=\frac{\sqrt{3} }{2} \\\\4cos^3\theta=4*\frac{\sqrt{3} }{2}*\frac{\sqrt{3} }{2}*\frac{\sqrt{3} }{2}-3*\frac{\sqrt{3} }{2}\\\\4cos^3\theta=\frac{3*\sqrt{3} }{2}-\frac{3\sqrt{3} }{2}\\ \\4cos^3\theta=\frac{3\sqrt{3} }{2}- \frac{3\sqrt{3} }{2}\\\\4cos^3\theta=0$