Question

1. Prove that :
sin 80º – cos 70°=
cos 50

Answer 1

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sin 80°-cos 70°=cos50°

Here (sin 80° -cos 70°) is LHS and cos 50° is RHS.

Formula to be used

• sin 80°=0.98
• cos 70°=0.34
• cos 50°=0.64

So,

LHS=sin 80°-cos 70°

=0.98-0.34

=0.64

RHS=cos 50°

=0.64

Hence,sin 80°-cos 70°=cos50° is proved.

Answer 2

Answer:

*Refer the attachment.