Дано: sin A=3/7. Найдите cos A, tgA

cos A = √(1 - sin²A) = √(1 - (3/7)²) = √(1 - 9/49) = √(40/49) = √40 / 7

tg A = sin A / cos A = (3/7) / (√40 / 7) = 3 / √40