# Difficult C4 Integral

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#1
Can anyone help me with this problem please?

http://gyazo.com/f536ca487f7c5cf866ff5f7814d1b78c
Sorry I didn't know how to input it properly on here, and it says to use the substitution x=sec(theta)

Now, I've found dx/d(theta) and got sec(theta)tan(theta)...and replaced dx with d(theta)sec(theta)tan(theta).... I think I also found the correct limits in terms on theta values. The problem I have is how to integrate this. Please tell me if I have done it right up to this stage, and then if you could help that would be great, cheers.
0
6 years ago
#2
(Original post by podrodow1)
Can anyone help me with this problem please?

http://gyazo.com/f536ca487f7c5cf866ff5f7814d1b78c
Sorry I didn't know how to input it properly on here, and it says to use the substitution x=sec(theta)

Now, I've found dx/d(theta) and got sec(theta)tan(theta)...and replaced dx with d(theta)sec(theta)tan(theta).... I think I also found the correct limits in terms on theta values. The problem I have is how to integrate this. Please tell me if I have done it right up to this stage, and then if you could help that would be great, cheers.
Yes

Do you know what you can do with that that you have
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#3
(Original post by TenOfThem)
Yes

Do you know what you can do with that that you have
Yeah I've made that into tan^2(theta)...but now the problem is I'm not sure how to integrate this. I tried using standard patterns but that didn't work, and I don't think by parts will work...will it?
0
6 years ago
#4
(Original post by podrodow1)
Yeah I've made that into tan^2(theta)...but now the problem is I'm not sure how to integrate this. I tried using standard patterns but that didn't work, and I don't think by parts will work...will it?
So what do you have now that you have done some cancelling

What do you think you need to integrate
0
6 years ago
#5
(Original post by Robbie242)
No, you have so instead integrate each part separately and noting that
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6 years ago
#6
(Original post by Robbie242)
No, you have so instead integrate each part separately and noting that
is in brackets, and being taken to the power of negative 3/2. It's also being multiplied by .

So you can't integrate and 1 separately.
0
6 years ago
#7
(Original post by TenOfThem)
Sorry I wasn't sure where the OP was, shouldn't really be giving advice without doing it myself I just assumed from your post. Will restrain myself next time
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6 years ago
#8
(Original post by Robbie242)
Sorry I wasn't sure where the OP was, shouldn't really be giving advice without doing it myself I just assumed from your post. Will restrain myself next time
You seemed to be doing a totally different question
0
6 years ago
#9
(Original post by StrangeBanana)
is in brackets, and being taken to the power of negative 3/2. It's also being multiplied by .

So you can't integrate and 1 separately.
Oh no don't worry I know that, I was just been stupid and not looking at the actual integral (thought after rearranging the integral boiled down to what TenofThem said )
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6 years ago
#10
(Original post by Robbie242)
Oh no don't worry I know that, I was just been stupid and not looking at the actual integral
Whoopsi-daisy!
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#11
(Original post by TenOfThem)
So what do you have now that you have done some cancelling

What do you think you need to integrate
I'm really unsure
0
6 years ago
#12
(Original post by podrodow1)
I'm really unsure
You have

Can you simplify that?
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#13
(Original post by TenOfThem)
You have

Can you simplify that?
Yes to sec/tan^2...but how did you get to that?
0
6 years ago
#14
(Original post by podrodow1)
Yes to sec/tan^2...but how did you get to that?
I thought that you said that you knew that
0
6 years ago
#15
Use the substitution
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#16
(Original post by TenOfThem)
I thought that you said that you knew that
I do, but I don't see how that became tan^3 on the bottom
0
6 years ago
#17
(Original post by Tarquin Digby)
Use the substitution
its C4 bro.
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#18
(Original post by TenOfThem)
I thought that you said that you knew that
Does the tan^2 cancel with the 2 in the bracket to produce tan^3?
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6 years ago
#19
(Original post by podrodow1)
I do, but I don't see how that became tan^3 on the bottom
You do not see why
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6 years ago
#20
(Original post by podrodow1)
Does the tan^2 cancel with the 2 in the bracket to produce tan^3?
yes
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