Solve sin3x plus cos3x equals 6?

If you want sin(3x) + cos(3x) = 6, then this is impossible. Sine and cosine will only return values between -1 and 1, so the expression sin(3x) + cos(3x) could only take values from -2 to 2, although even this is to great as sine and cosine of the same number will never both be 1 or -1.

Similarly, if you want a solution to sin3x + cos3x = 6, then this is also impossible, because any power of a number between -1 and 1 will itself be between -1 and 1.