1)3sin²π÷2-4tg²π÷4-3cos²π÷6+3ctg²π÷2 2)tg5π÷4×sinπ÷3-cos7π÷6×sin3π÷2 3)sinα=3÷4,0≤α≤π÷2 4)ctgα=2÷3,π≤α≤3π÷2 5)ctgα-cosα-1÷sinα 6)(sinβ×ctgβ)²+(cosβ×tgβ)2

1)3*1²-4*1²-3*(√3/2)²+3*0²=3-4-2,25+0=-3,25
2)1*√3/2-(-√3/2)*(-1)=√/2-√3/2=0
3)sina=3/4,0≤a≤π/2
a=arcsin3/4
4)ctga=2/3,π≤a3π/2
a=π+arcctg2/3
5)ctga-(cosa-1)/sina=cosa/sina -(cosa -1)/sina=
=(cosa-cosa+1)/sina=1/sina
6)(sinb*ctgb)²+(cosb*tgb)²=(sinb*cosb/sinb)²+(cosb*sinb/cosb)²=
=cos²b+sin²b=1