Question

Тригонометрия. Прошу 28,29,30 примеры. Буду благодарна

Answer 1

$28)sin ^{2} x+cos ^{2} x+tg ^{2} x=1+tg ^{2} x= frac{1}{cos ^{2} x} \ \ 29) sec ^{2} a-tg ^{2} a-sin ^{2} x= frac{1}{cos^{2} x} - frac{sin^{2} x}{cos ^{2} x} -sin^{2} x= frac{1-sin ^{2} x}{cos ^{2} x} -sin^{2} x= \ = frac{cos ^{2} x}{cos^{2} x} -sin ^{2} x=1-sin^{2} x=cos ^{2} x \ 30) \ 1) frac{sin alpha *sin beta }{cos alpha *cos beta } =tg alpha *tg beta \ 2) frac{cos alpha *cos beta }{sin alpha *sin beta } =ctg alpha *ctg beta$