I would like to transform trigonometric expressions according to my preferred routes. E.g.: a: 2*sin(x)^2-3*cos(x); to be tranformed by applying the rule cos(x)^2 = 1 - sin(x)^2 I have unsuccessfully tried trigrat, trigexpand, trigsimp Any hints? I would also like to solve that equation, by applying given rules. Thank you -- Pol