Evaluate:cos 48°- sin 42°

1.	Evaluate:cos 48°- sin 42°
Answer» We know that, cos (90° − θ) = sin θ. So, cos 48° – sin 42° = cos (90° − 42°) – sin 42° = sin 42° – sin 42° = 0 Thus the value of cos 48° – sin 42° is 0.

Answer»

We know that, cos (90° − θ) = sin θ.

So,

cos 48° – sin 42°

= cos (90° − 42°) – sin 42°

= sin 42° – sin 42°

= 0

Thus the value of cos 48° – sin 42° is 0.

Discussion