Question

cos theta - sin theta =
1
Prove Cos theta + sin theta = 1
or - 1​

Answer 1

Answer:

ANSWER

Given

cosθ+sinθ=1

(cosθ+sinθ) ^2 =1 ^2

cos ^2 θ+sin ^2 θ+2sinθcosθ=1

1+2sinθcosθ=1

2sinθcosθ=0

sinθcosθ=0

Now (cosθ−sinθ) ^2

=(cosθ+sinθ) ^2−4sinθcosθ

=1 ^2−4×0

=1

(cosθ−sinθ) ^2=1

cosθ−sinθ=±1

∴ Hence proved

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