cosec²5α
Пошаговое объяснение:
sin^2a+cos^2a+1/tg^2 5a
sin^2a+cos^2a=1
sin^2a+cos^2a+1/tg^2 5a=1+1/tg^2 5a=(tg^2 5a+1)/tg^2 5a, так как
tg^2 5a=sin^2 5a/cos^2 5a, то
(tg^2 5a+1)/tg^2 5a=(cos^2 5a*sin^2 5a/cos^2 5a+cos^2 5a)/sin^2 5a=
=(sin^2 5a+cos^2 5a)/sin^2 5a=1/sin^2 5a=cosec²5α
