Question

sin[3 sin^-1 (0.4)] = ______.

Options

• 0.466

• 0.256

• 0.944

• 0.764

Answer 1

sin[3 sin^-1 (0.4)] = 0.944.

Explanation:

Let E = sin[3 sin^-1 (0.4)]

put sin^-1 (0.4) = θ ⇒ sin θ = 0.4

∴ E = sin (3θ) = 3 sin θ - 4 sin³ θ

= 3(0.4) - 4(0.4)³

= 1.2 - 4(0.064)

= 1.2 - 0.256

= 0.944