Question

2
7
А A
sin
) - sin² ( 7 / 2 - 2 / ) = F Sin A
8
2​

Answer 1

Answer:

Step-by-step explanation:

L.H.S.=sin2(π8+A2)−sin2(π8−A2)

=(sin(π8)cos(A2)+cos(π8)sin(A2))2−(sin(π8)cos(A2)−cos(π8)sin(A2))2

As a2−b2=(a+b)(a−b), so it becomes

=(sin(π8)cos(A2)+cos(π8)sin(A2)+sin(π8)cos(A2)−cos(π8)sin(A2))(sin(π8)cos(A2)−cos(π8)sin(A2)−sin(π8)cos(A2)+cos(π8)sin(A2))

=4(sin(π8)cos(A2)(cos(π8)sin(A2))

=(2sin(π8)cos(π8))(2sin(A2)cos(A2))

=sin(2⋅π8)sin(2⋅A2)

=sinπ4sinA

=12‾√sinA=R.H.S.

follow me plz