Question

Упростить
1)sinB ctgB
2)sin²a/1+cosA
3)cosB tgB+sinB
4)1-cos²a/1-sin²a

Answer 1

$1)sin beta *ctg beta = frac{sin beta *cos beta }{sin beta } =cos beta \ \ 2) frac{sin^{2} alpha }{1+cosa} \ \ 3)cos beta tg beta +sin beta = frac{cos beta *sin beta }{cos beta } +sin beta =sin beta +sin beta = \ =2sin beta$

$4) frac{1-cos ^{2} alpha }{1-sin^{2} alpha } = frac{sin ^{2} alpha +cos ^{2} alpha-cos^{2} alpha }{sin ^{2} alpha +cos ^{2} alpha -sin ^{2} alpha } = frac{sin^{2} alpha }{cos^{2} alpha } = tg^{2} alpha$

Answer 2

=(

Answer 3

во втором 2sin^2(a/2)

Answer 4

во втором все верно

Answer 5

во втором не так

Answer 6

Разность квадратов