Integrate 1 + sinx/cos x
Maths and statistics discussion, revision, exam and homework help.
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Re: Integrate 1 + sinx/cos xLook at post no. 9, i have hinted towards this method.(Original post by James A)
have you learnt the integration rule, where if you differentiate the denominator, you get the value that appears in the numerator. hence ln(your original function)
have you come across this before?
this could prove useful here.
someone else correct me if im wrong
WHOOPS PARTIAL FRACTIONS ARE THE WAY FORWARD
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Re: Integrate 1 + sinx/cos xyou wally.(Original post by blacklistmember)
I'm sorry but i'm too busy to help you -
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Re: Integrate 1 + sinx/cos xno idea(Original post by f1mad)
Why post then? -
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Re: Integrate 1 + sinx/cos xyeah i know, but i forgot to include your post in my response. Sorry.(Original post by raheem94)
Look at post no. 9, i have hinted towards this method. -
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Re: Integrate 1 + sinx/cos xi had to look that up :P(Original post by James A)
you wally. -
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Re: Integrate 1 + sinx/cos x(Original post by f1mad)
It's not.
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Re: Integrate 1 + sinx/cos xBoth ways, can be used. Your method is faster, but doing partial fractions also takes moments.(Original post by f1mad)
It's not. -
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Re: Integrate 1 + sinx/cos xPlease put in brackets with things like this, i.e. (1+u)/(1-u²). Not doing so has led to some misleading advice because people think you mean(Original post by This Honest)
integrate: 1 +u/1-u^2 ??
and 
instead of 
and 
.
Anyway, you got the right answer
.
(In fact you can remove the mod signs since
for all 
.)
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Re: Integrate 1 + sinx/cos xI beg to differ: your partial fraction isn't the same as the function of the substitution (see Nuodai's post).(Original post by raheem94)
Both ways, can be used. Your method is faster, but doing partial fractions also takes moments. -
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Re: Integrate 1 + sinx/cos xSound like my maths teacher now(Original post by nuodai)
Please put in brackets with things like this, i.e. (1+u)/(1-u²). Not doing so has led to some misleading advice because people think you mean and instead of and .
Anyway, you got the right answer.
(In fact you can remove the mod signs since for all .)
Thanks, I will next time
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Re: Integrate 1 + sinx/cos xSo we were solving the wrong question. The question was different, right?(Original post by f1mad)
I beg to differ: your partial fraction isn't the same as the function of the substitution (see Nuodai's post). -
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Re: Integrate 1 + sinx/cos xYeah..sorry that was my fault. As noudai said...I caused confusion in the way I wrote it out(Original post by raheem94)
So we were solving the wrong question. The question was different, right?
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Re: Integrate 1 + sinx/cos xWhy have you made u equal to cos x here?(Original post by nuodai)
If you substitute
then you get 
, so you get 
on the denominator. How might you write in terms of 
?
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Re: Integrate 1 + sinx/cos xNo problem, but please learn LaTeX, it only takes a few minutes to learn it.(Original post by This Honest)
Yeah..sorry that was my fault. As noudai said...I caused confusion in the way I wrote it out
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Re: Integrate 1 + sinx/cos xI'll try and learn it when I'm having difficulty with C4 again before I post the problem(Original post by raheem94)
No problem, but please learn LaTeX, it only takes a few minutes to learn it.
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Re: Integrate 1 + sinx/cos xTypo; I'd set(Original post by TheGrinningSkull)
Why have you made u equal to cos x here?
. If I'd actually set then I wouldn't have got , after all.
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Re: Integrate 1 + sinx/cos xAn alternative approach would be to notice that
, which after a bit of cancelling leads to logs directly.
EDIT: just realised the OP was asked for a specific sub, so this can be ignored.Last edited by Farhan.Hanif93; 01-04-2012 at 18:58. -
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Re: Integrate 1 + sinx/cos x(Original post by Farhan.Hanif93)
An alternative approach would be to notice that, which after a bit of cancelling leads to logs directly.
thanks for that.
I'd stick with my method though
