3,4 примеры пожалуйста!

3) У меня буквы гамма нет, я буду писать a[latex]cos(a)+ \frac{2sin^2(a)-1}{sin(a)+cos(a)}= cos(a)+ \frac{2sin^2(a)-sin^2(a)-cos^2(a)}{sin(a)+cos(a)}=[/latex] [latex]=cos(a)+ \frac{sin^2(a)-cos^2(a)}{sin(a)+cos(a)} =cos(a)+ \frac{(sin(a)+cos(a))(sin(a)-cos(a))}{sin(a)+cos(a)} =[/latex] [latex]=cos(a)+sin(a)-cos(a)=sin(a)[/latex] 4) [latex] \frac{1+ctg^2(x)}{tg(x)+ctg(x)} = \frac{1+cos^2(x)/sin^2(x)}{tg(x)+ctg(x)} = \frac{sin^2(x)+cos^2(x)}{sin^2(x)*(tg(x)+ctg(x))} =[/latex] [latex]= \frac{1}{sin^2(x)*( \frac{sin(x)}{cos(x)} + \frac{cos(x)}{sin(x)} )} =\frac{1}{sin^2(x)* \frac{sin^2(x)+cos^2(x)}{sin(x)*cos(x)}} = \frac{sin(x)*cos(x)}{sin^2(x)*1} =ctg(x)[/latex]