Carman3
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#1
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How do I solve this question:

(4+t^2) ds/dt = 1

You can't integrate 1/(4+t^2) and you can't split it into partial fractions I'm guessing because you can't factorise it so how do you solve it?
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NotNotBatman
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(Original post by Carman3)
How do I solve this question:

(4+t^2) ds/dt = 1

You can't integrate 1/(4+t^2) and you can't split it into partial fractions I'm guessing because you can't factorise it so how do you solve it?
You can integrate it, let t = 2 tanx and integrate via substitution.
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Carman3
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(Original post by NotNotBatman)
You can integrate it, let t = 2 tanx and integrate via substitution.
How do you know to let t = 2tanx aas it's not given. Also will questions like this be too hard to come up in the exam
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RDKGames
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(Original post by Carman3)
How do you know to let t = 2tanx aas it's not given. Also will questions like this be too hard to come up in the exam
You just need to get used to the fact that anything in the form \displaystyle \frac{dy}{dx}=\frac{1}{a^2+x^2} can be integrated by using substitution x=a\tan(u)
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NotNotBatman
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(Original post by Carman3)
How do you know to let t = 2tanx aas it's not given. Also will questions like this be too hard to come up in the exam
Oh wait, I've just realized you said FP2 and not 3; edexcel is it ?

Right now, I can't think of anything else, but I wouldn't imagine this would be in FP2. Did you do all previous steps correctly?
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Carman3
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(Original post by NotNotBatman)
Oh wait, I've just realized you said FP2 and not 3; edexcel is it ?

Right now, I can't think of anything else, but I wouldn't imagine this would be in FP2. Did you do all previous steps correctly?
I have a book where all the FP's are combined but it was a practice question from the first order D.E topic so I figured it's from fp2. I did all the steps correctly
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NotNotBatman
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(Original post by Carman3)
I have a book where all the FP's are combined but it was a practice question from the first order D.E topic so I figured it's from fp2. I did all the steps correctly
If this is for Edexcel, that would be in FP3.

But if you need to know it, refer to what RDKGames has written; integrals whose answers involve inverse trig functions are provided in the formula book.
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