Question

sin (70degree+0)-cos (20degree-0)=0

Answer 1

Look

sin(70+0) - cos ( 20- 0)

sin (70+ 0) - sin (90- 20 + 0)

sin (70+0 ) - sin (70+0 )

=¶ 0.


thus RHS = LHS. proved.



hope it may help. if any problem then discuss here.

Answer 2

sin(70+0)-cos(20-0)=0.

=sin70-cos20=0

=sin(90-20)-cos20=0.

=cos20-cos20=0 which is true.

Hence proved.