Question

.prove that cos (90-A).sinA + sin(90 - A).cosA = 1 ​

Answer 1

Answer:

See Explanation

Step-by-step explanation:

$cos (90-A).sinA + sin(90 - A).cosA = 1 \\ \\ LHS = cos (90-A).sinA + sin(90 - A).cosA \\ \\ = sinA.sinA + cosA.cosA\\ \\ = sin ^{2} A + cos^{2} A \\ \\ = 1 \\ \\=RHS\\\\ reason \\ cos (90- \theta) = sin \theta \\ sin (90- \theta) = cos \theta \\ sin ^{2} \theta + cos^{2} \theta = 1 \\ \\ thus \: proved$