# Integration (substituition)

1. May 2, 2014

### delsoo

1. The problem statement, all variables and given/known data

for this question, the question only stated SUITABLE substituition, what substituition should i use? this substituion does not involve trigo functions , am i right? P/S : i'm just asking opinion, not the full working.

2. Relevant equations

3. The attempt at a solution

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2. May 2, 2014

### Dick

No, you don't need trig functions. Use a substitution that will get rid of the square root.

3. May 2, 2014

### delsoo

what should i sub? how to determine the substitution for this type of question? can i sub u= surd x ? or u=( 1+ surd x ) ? or u=(( 1+ surd x ) sqrt)

4. May 2, 2014

### Curious3141

Why don't you try it and see? Both $u = \sqrt{x}$ and $u = 1 + \sqrt{x}$ work but one gives a quicker and neater answer.

5. May 4, 2014

### delsoo

for this type of question, can i use any substituition i like such as u=(1+ surd x )^2 ?

6. May 4, 2014

### Dick

You can TRY any substitution you like, they won't all help you to integrate. Don't forget when you substitute u=f(x) you also have to find du so you can figure out how to express the dx part in terms of u.