Question

Даю 30 баллов. Спасибо заранее.

Answer 1

Ответ:

Объяснение:

1) $dfrac{sin^2alpha -cos^2alpha +cos^4 alpha }{cos^2alpha -sin^2alpha +sin^4 alpha } = dfrac{sin^2alpha -cos^2alpha (1-cos^2 alpha) }{cos^2alpha -sin^2alpha (1-sin^2 alpha) } =$

$= dfrac{sin^2alpha -cos^2alpha sin^2 alpha }{cos^2alpha -sin^2alpha cos^2 alpha } = dfrac{sin^2alpha(1 -cos^2alpha) }{cos^2alpha(1 -sin^2alpha) }= \\\= dfrac{sin^2alphacdot sin^2 alpha}{cos^2alpha cdot cos^2 alpha } = tg^4 alpha$

2) $dfrac{3sin^2alpha+cos^4alpha}{1+sin^2alpha +sin^4alpha } = dfrac{3sin^2alpha+(1-sin^2alpha)^2}{1+sin^2alpha +sin^4alpha }=$

$= dfrac{3sin^2alpha+1-2sin^2alpha+sin^4 alpha }{1+sin^2alpha +sin^4alpha }=dfrac{1+sin^2alpha +sin^4alpha }{1+sin^2alpha +sin^4alpha }= 1$

Answer 2

К заданию 3) пока нет мыслей ))) Удачи!