What is the 'chain rule'?
The chain rule is incredibly useful when differentiating compositions of funcions.
Until now you have really only met dy/dx as your derivative. By imagining dy/dx as a fraction, you can transform it into something using another parameter, for example t.
For example, just how 1/2 x 2/3 = 2/6 (multiply numerater, multiply denominator), dy/dx x dt/dy = dydt/dxdy, and the 'dy' values would cancel, giving dt/dx. This is only for this level of mathematics however, as in reality, you can't treat dy/dx as a fraction!
JA
Related Maths A Level answers
All answers ▸Differentiate and find the stationary point of the equation y = 7x^2 - 2x - 1.
A curve has equations: x=2sin(t) and y=1-cos(2t). Find dy/dx at the point where t=pi/6
Given that y=(sin4x)(sec3x), use the product rule to find dy/dx
The curve C has equation y = x^3 - 3x^2 - 9x + 14. Find the co-ordinates and nature of each of the stationery points of C.