tan(x)*sin^2(x) = 2tan(x) ====> tan(x)*(sin^2(x) - 2) = 0. Since sin^2(x) is always LESS THAN 2, it implies tan(x) = 0. The solutions to this equation are x = , k = 0, +/-1, +/-2, . . . ("k" is any integer number). ANSWER