You are Here: Home

# differential equation:

Announcements Posted on
AQA GCSE physics P1 unofficial mark scheme 05-05-2016
1. i would like to know what your answer to this question is:

Solve: dy/dx = Sqrt(y^2-1) with i.c. y(1)=1.

my book gets another mathematica gets another
maple gets another

if i exponentiate the solution, i get one for i can`t explicitly solve for y
if i take the solution as being inverse hyperbolic, i (apparently according to Maple) get the wrong answer also
(hyperbolicly, i get y(x) = Cosh(x)

what am i missing (appart from a few grey cells this time of night!)
2. Arccosh(y)=x-1 => y=Cosh(x-1) ? mathematica gets cosh(1-x)!!
3. (Original post by Hasufel)
Arccosh(y)=x-1 => y=Cosh(x-1) ? mathematica gets cosh(1-x)!!
They're the same.

cosh(x-1) = 0.5(e^x-1 + e^-x+1)

cosh(1-x) = 0.5(e^-x+1 + e^x-1)
4. cheers!

best go to bed i suppose!

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
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
1. Oops, you need to agree to our Ts&Cs to register

Updated: June 21, 2012
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

### AQA GCSE maths

Check the unofficial mark scheme

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read here first

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams