Question

plz solve 10 the one plz

Answer 1

cos A - sin A = 1

Square both sides to get,

-2sin A cos A = 0

Now,

sin A + cos A = √[(sin A+ cos A)²]

=√[sin²A+cos²A+2sin A cos A]

=√(1+0)

=±1

Answer 2

Here cos2A means cos^2{A}

cosA - sinA = 1
or, cos2A - 2sinAcosA + sin2A = 1
or, 1 - 2sinAcosA = 1
or, 2sinAcosA = 0

(cosA + sinA)^2 = cos2A + 2sinAcosA + sin2A
= cos2A + 0 + sin2A
= 1

Hence, (cosA + sinA)^2 = 1
or, cosA + sinA = +/- _/1
or, cosA + sinA = +/- 1

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