Given y=x^3+5x+3 find dy/dx when x=3

The question can be broken into two steps, 

1) dy/dx is asking to differentiate y=x3+5x+3 with respect to x

Differentiating we multiply by the current power and lower this powers value by 1. ( Constants differentiate to nothing )

i.e  x3 goes to 3x2

dy/dx=  3x2+5

2) Next we need to find the value of dy/dx when x=3 done simply by substituting all x's in the equation by 3

dy/dx=  3*(3)+ 5 = 32

RL

Related Maths GCSE answers

All answers ▸

x - 2y = 1 , x^2 + y^2 = 13 find the solutions to this quadratic equation


320 people go on a coach trip. Each trip holds 53 people. Gary says 6 coaches are needed. Is Gary correct?


Simplify: 2x + 6y + 2y - x


Work out 1 1/5 ÷ 3/4. Give your answer as a mixed number in it's simplest form