Hey there! Sign in to join this conversationNew here? Join for free to post

# Integration By Substitution

Announcements Posted on
Would YOU be put off a uni with a high crime rate? First 50 to have their say get a £5 Amazon voucher! 27-10-2016
1. Hi Everyone,

I've just been going over this question:

Find the integral of cosh(u)/(1+sinh^2(u))

Now i got the correct answer + tan^-1(sinh(u))

But a step in the process has me confused.

When you substitute x=sinh(u) at the start, the cosh(u)'s cancel and your left with the intergral of 1/(1+x^2) dx could you not just integrate this to get (1/(2x))*(ln(1+x^2)) + C as the derivative of 1/(2x))*(ln(1+x^2)) + C would be 1/(1+x^2) right? or am i just making a silly mistake somewhere?

Cheers
2. Oops, forget all that (can you not delete threads these days)...

Realised the derivative of 1/(2x))*(ln(1+x^2)) is no where near that...

Write a reply…

Submit reply

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
that username has been taken, please choose another Forgotten your password?
2. this can't be left blank
this email is already registered. Forgotten your password?
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
your full birthday is required
1. Oops, you need to agree to our Ts&Cs to register
2. Slide to join now Processing…

Updated: May 16, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

Find out here

### How to cope with a heavy workload

Poll
Study resources

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.