If cos (sin-1 2/5 + cos-1 x) = 0, then x is equal to(a) 1/5 (b) 2/5

1.	If cos (sin-1 2/5 + cos-1 x) = 0, then x is equal to(a) 1/5 (b) 2/5 (c) 0 (d) 1
Answer» (b) 2/5 Given, cos (sin^-1 2/5 + cos^-1 x) = 0 So, this can be rewritten as sin^-1 2/5 + cos^-1 x = cos^-1 0 sin^-1 2/5 + cos^-1 x = π/2 cos^-1 x = π/2 – sin^-1 2/5 cos^-1 x =cos^-1 2/5 [Since, cos^-1 x + sin^-1 x = π/2] Hence, x = 2/5

If cos (sin-1 2/5 + cos-1 x) = 0, then x is equal to(a) 1/5 (b) 2/5 (c) 0 (d) 1

Answer»

(b) 2/5

Given,

cos (sin^-1 2/5 + cos^-1 x) = 0

So, this can be rewritten as

sin^-1 2/5 + cos^-1 x = cos^-1 0

sin^-1 2/5 + cos^-1 x = π/2

cos^-1 x = π/2 – sin^-1 2/5

cos^-1 x =cos^-1 2/5 [Since, cos^-1 x + sin^-1 x = π/2]

Hence,

x = 2/5