Question

does anyone know how to solve​

Answer 1

I hope it will help u

Answer 2

To prove -- cosA+sinA = +-1

Proof ---cosA-sinA=1
squaring on the both sides
cos^2A+sin^2A-2cosA×sinA=1
1-2cosA×sinA=1
-2cosA×sinA=0
cosA ×sinA=0

(cosA+sinA)^2
cos^2A+sin^2A+2cosA×sinA
1+2×0
1

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