Question

Evaluate cos 45° + sin 225°

Answer 1

sin225 ∘=sin(180∘+45∘). =sin180∘cos45∘+cos 180∘sin45∘. =(0)(1√2)+(−1)1√2. = −1√2.

Answer 2

Answer:

sin225=-sin45

so

cos45-sin45=cos45-sin(90-45)

cos45-cos45=0