Question

Найдите sinA,если cosA=15/17

Answer 1

sin^2+cos^2=1- основное тригонометрическое тождество.
sin^2+(15/17)^2=1
sin^2+225/289=1
sin^2=1-225/288
sin^2=(289-225)/289
sin^2=64/289
sin=8/17; sin=-8/17