Question

(a) cos 9° + sin 9° = root2 sin 54°​

Answer 1

Step-by-step explanation:

we start our process of prove it from R.H.S

√2sin(54)

=√2sin(45+9)

=√2sin45.cos9+cos45.sin9 (sin(a+b))=sinA.cosB+cosA.sinB

=√2(1/√2×cos9+1/√2×sin9)

(if we get common to 1/√2 then

=√2×1/√2(cos9+sin9)

=cos9+sin9 (L.H.S) (proved)