Question

answer of question no. 4 ​

Answer 1

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

sin^-1(2/5 ) + cos^-1(x) = sin^1sin0

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

cos^-1(sqrt21/5) = cos-1(π/2 +x)

21/5 = π/2 +x

x = 21/5 -π/2