1.

sinx + i cos 2x and cos x - i sin2x are conjugate to each other for(A) x=nπ (B) x=(n+1/2)π/2 (C) x=0 (D) no value of xA. `x = npi`B. `x = ("n" +(1)/(2))(pi)/(2)`C. x=0D. No value of x

Answer» Correct Answer - D
let `z= sinx +icos2x `
and `barz = sinx - 2x " "...(i)`
Given that, `barz = cosx - isin 2x" "...(ii)`
`:. sinx - icon 2x = cos x - isin 2x`
`rArr sin x = cos x and cos2x = sin2 x `
`rArr tanx = 1 "and" 2x =1 `
`rArr tan x = "tan"(pi)/(4) "and" 2x = "tan"(pi)/(4)`
`rArr x =npi + (pi)/(4) "and" 2x = 2pi + (pi)/(4) `
`rArr 2x - x = 0 rArr x = 0 `


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