упростить
1-sina/cosa+tga
1/1+cosa+1/cos-a
ctg2b(cosb-1)+1
tgb+1/1+ctgb
номер 79

1(1-cosa)/cosa+sina/cosa=(1-sina+sina)/cosa=1/cosa21/(1+cosa)+1/(1-cosa)=(1-cosa+1+cosa)/(1-cos²a)=2/sin²a3cos²b/sin²b*(-sin²b)+1=-cos²b+1=sin²b4(sinb/cosb+1):(1+cosb/sinb)=(sinb+cosb)/cosb*sinb/(sinb+cosb)==sinb/cosb=tgb