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# AQA C4 Differential equation question help watch

1. I'm stuck on the following differential equation question, as usual I can't seem to spot where I've gone wrong, I've tried re doing the question and reading over my answer and trying different things and I've got the same result.
Here is the question, it's 7) the question is 'Find the solution of the differential equation that satisfies the given condition. Where possible give your answers in a simplified explicit form':

Here is how I approached the question:

I ended up with x= t-1 when the answer is y=1/2(t+1)
Any insights on how to do this question will be greatly appreciated as I'm really confused, thanks
2. (Original post by Sayless)
I'm stuck on the following differential equation question, as usual I can't seem to spot where I've gone wrong, I've tried re doing the question and reading over my answer and trying different things and I've got the same result.
Here is the question, it's 7) the question is 'Find the solution of the differential equation that satisfies the given condition. Where possible give your answers in a simplified explicit form':

Here is how I approached the question:

I ended up with x= t-1 when the answer is y=1/2(t+1)
Any insights on how to do this question will be greatly appreciated as I'm really confused, thanks
the problem is the line where you get rid of the logs.
it is wrong there
3. (Original post by TeeEm)
the problem is the line where you get rid of the logs.
it is wrong there
Nice spot thanks I see where I went wrong, I should have made e^ln not just instantly got rid of the ln, I made it:

x= e^ln(t+1)+A
x=(t+1)(e^A)
x= B(t+1)
then ended with x= 1/2(t+1)

the answer for some reason is y=1/2(t+1) i'm not sure why they've switched the x, they haven't switched that in other questions
4. (Original post by Sayless)
Nice spot thanks I see where I went wrong, I should have made e^ln not just instantly got rid of the ln, I made it:

x= e^ln(t+1)+A
x=(t+1)(e^A)
x= B(t+1)
then ended with x= 1/2(t+1)

the answer for some reason is y=1/2(t+1) i'm not sure why they've switched the x, they haven't switched that in other questions
a typo?
5. (Original post by TeeEm)
a typo?
probably yeah, thanks for all your help
6. (Original post by Sayless)
probably yeah, thanks for all your help
no worries
7. When you have logs on both sides it can be helpful for some people to write the constant as lnA rather than A, it seems to help some people when it comes to getting rid of the logs.

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