Question

if angle A + Angle B + angle C is equal to 180 degree, then show that sin (b + c) close is equal to sign a ​

Answer 1

Step-by-step explanation:

see the attachement. very straight forward

Answer 2

Step-by-step explanation:

A+B+C=180

B+C=180 - A

SIN (B+C) = SIN (180- A)

=SIN {90+(90-A)}

=COS (90-A)

=SIN A