Question

if sin4A=cos(A-20) find value of A

Answer 1

Sin 4A = cos (A-20)
=> cos (90-4A) = cos (A - 20)
=> 90 - 4A = A - 20
=> 5A = 110
=> A = 22°

Answer 2

We know that ,cos(90-x) = sinx

sin 4A = cos (A-20)
= cos (90-4A) = cos (A - 20)
=90 - 4A = A - 20
=5A = 110
= A = 110/5 = 22 .

Hope helped!