# AQA A Level Maths: Pure复习笔记8.2.2 Integrating Other Functions (Trig, ln & e etc)

### Integrating Other Functions (Trig, ln & e etc)

#### Isn’t integration just the reverse of differentiation?

• Yes, but remember “+c”, the constant of integration …
• … unless finding a definite integral
• Recognising common results helps to make integration easier (See Differentiating Other Functions)

#### How do I integrate exponentials (ex)?

• The gradient of ekx is kekx
• ie y = ekx, dy/dx = kekx
• The reverse applies when integrating
• This is an example of reverse chain rule

#### Integrating sin and cos

• Note the minus in the integral of sin x
• The integral of tan x is ln|sec x| + c

#### Exam Tip

• Make sure you have a copy of the formula booklet during revision but don't try to remember everything in the formula booklet.
• However, do be familiar with the layout of the formula booklet – you’ll be able to locate quickly whatever you are after, and you do not want to be searching every line of every page!
• For formulae you think you have remembered, use the booklet to double-check.