Question

упростить (1-ctga)^2+(1+ctga)^2

Answer 1

$(1-ctg alpha )^{2} +(1+ctga)^{2} =1+ctg ^{2} a-2ctga+1+ctg^{2} a+2ctga= \ =2+2ctg^{2} a=2(1+ctg^{2} a)=2* frac{1}{sin ^{2} a} = frac{2}{sin^{2} a}$

Answer 2

$(1-ctga)^2+(1+ctga)^2=\1-2ctga+ctg^2a+1+2ctga+ctg^2a=\2+2ctg^2a=\2(1+ctg^2a)=2* frac{1}{sin^2a}=frac{2}{sin^2a}$