Differentiation: How to use the chain rule

If y is a function of u, which itself is a function of x, then 

dy/dx=(dy/du) x (du/dx)

Differentiate the outer function and multiply by the derivative of the inner function.  

To illustrate this rule, look at the example below:

y=(2x+3)10

in which y=u10 and u=2x+3

Now,

dy/du=10u9=10(2x+3)9

du/dx=2

The chain rule then gives

dy/dx=(dy/du) x (du/dx) = 10(2x+3)9(2) = 20(2x+3)9

 

NH

Related Maths A Level answers

All answers ▸

What is the turning point on the curve f(x) = 2x^2 - 2x + 4


If we have a vector 4x + 6y + z and another vector 3x +11y + 2z then what is the angle between the two?Give the answer in radians


Can you help me understand how Arithmetic sequences work?


integrate function (x^4+3x)/(x^2) with respect to x