Find the equation of the tangent to the curve x=cos(2y+π)x = \cos(2y + \pi)x=cos(2y+π) at (0,π4)\displaystyle \left(0, \frac{\pi}{4}\right)(0,4π).
Give your answer in the form y=ax+by = ax + by=ax+b, where a a\,a and b b\,b are constants to be found.
4 exam-style questions on Edexcel A Level Old Maths Trigonometry. Each one has a worked solution and a mark scheme showing where the marks go.