I have a maths B (Grade 11 & 12 Advanced) exam on monday and im studying up for my whole weekend. D=

Anyway one question that I need help for is:

y = tan^2 3x

The answer I got in the end after using the quotient rule was

dy/dx = 6cos3x * cos^2 3x + sin^2 3x * 6sin 3x / cos^3 3x

The denominator is correct but the answer says that the numerator is 6sin3x

Can you please help me using tanx = sinx / cosx not sec^2 x

Thanks to anyone who can help me =)