Question

Упростите выражение
1.ctg a *tg a -cos^2 a
2.cos(pi/2-a) / ctg (2pi-a)
3.√2/2sin a +sin(pi/4-a)

Answer 1

1) ctga*tga-cos^2 a=1-cos^2a=sib^2a
2) cos(pi/2-a) / ctg (2pi-a)=sina/(-ctga)=-sina*tga=sin^a/cosa
3).√2/2sin a +sin(pi/4-a)=√2/2sin a +sin(pi/4)*cosa-sina*cos(pi/4)=
=√2/2sin a +√2/2cos a -√2/2sin a =√2/2cosa