korzystajac ze wzoru sin alfa+beta= sin alfa *cos beta+cos alfa *sin beta OBLICZ: a) dokładna wartosc sin alfa+beta wiedzac,ze sin alfa= 4/5 a cos beta = 15/17

sin ( alfa + beta) = sin alfa * cos beta + cos alfa*sin beta ===================================================== sin alfa = 4/5 zatem   cos^2 alfa = 1 - sin^2 alfa = 1 - (4/5)^2 = 25/25 - 16/25 = 9/25 cos alfa = 3/5 ============= cos beta = 15/17 zatem  sin^2 beta = 1 - cos^2 beta = 1 - (15/17)^2 = 289/289 - 225/289 = 64/289 sin beta = 8/17 ============== Mamy więc sin(alfa + beta) = (4/5)*(15/17) + (3/5)*(8/17) = 60/85 + 24/85 = 84/85 ================================================================