Question

anyone plz help me in this problem

Answer 1

cos(36+54)
I hope this is the answer
because it looks like a formula
cos(A+B)=Cos(A)cos(B)-sin(A)sin(B)...

Answer 2

Hey there !

cos 36° cos 54° - sin 36° sin 54° = 0

LHS ,

cos 36° cos 54° - sin 36° sin 54

cos 36° cos(90-36) - sin 36° sin (90-36)

cos 36° sin 36° - sin 36° cos 36 °

cos 36° ( sin 36° - sin 36° )

cos 36° × 0.

0

RHS ,

0

so , LHS = RHS