Q33 of 90 Page 7

If , then show that sin α + cos α = cos x.

Given


Dividing numerator And denominator on RHSBy cos α,




We know that





Consider sin α + cos α,



We know that sin(A +B) = sinA cosB + cosA sinB And cos(A +B) = cosA cosB - sinA sinB





= √2 cos x


∴ sin α + cos α = √2 cos x


Hence proved.


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