Найти тангенс, если 25синyс^2+10косинус^2=13

25sin²x + 10cos²x = 1315sin²x + 10sin²x + 10cos²x = 1315sin²x + 10(sin²x + cos²x) = 13sin²x + cos²x = 115sin²x + 10 = 1315sin²x = 13 - 10 = 35sin²x = 1sin²x = 1/5cos²x = 1 - sin²x = 1 - 1/5 = 4/5tg²x = sin²x/cos²x = (1/5)/(4/5) = 1/4tgx₁ = 1/2tgx₂ = - 1/2