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)
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НикаВодолей
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
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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