Question

If A=45°, verify that
(1) sin 2A = 2 sinA cos A,
(2) Cos 2A=1 – 2 sin^2A​

Answer 1

Step-by-step explanation:

sin 2*45=sin 90=1......(1)

2sin 45 cos 45=2*1/√2*1/√2

=2/2=1......(2)

so sin 2a=2sina cos a

cos 2*45=cos 90=0

1-2sin²45=1-2*1/2=1-1=0