Hey All!

I just wanted to check, if a question asks us to integrate a function using integration by parts, do I strictly need to follow the formula booklet's formula for integration by parts, or may I use (the significantly faster) tabular integration by parts method? Also, does anyone have any specific tips on deciding whether to integrate a function by parts or use u-substitution?

Thanks in advance!

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Posted (edited)

I think I know the table method you are referring to; that's also integration by parts and it's the same formula just expressed visually different. Usually it's quite obvious you are doing integrating by parts so you can get the method marks for those. These method marks are given even if work is not shown but you get the right answer. Just to be extra safe, you can always write "integrate by parts" to show you know what you are doing, but that's not necessary. 
Special trig u-substitutions are provided by IB. Eg. let u = a cos x. 
If the integrand can be written as g'(x) * f(g(x)) then u substitution works directly. like 2t * e^(t2)

Typically when you have trig functions to power of 1 (cos x, sin x etc), or ln x or e^x, or x*f(x) or a combination, then by parts often works out nicely if direct antiderivative is hard to find. For many trig integrands you need some identities to express them in nice integrands.

Edited by kw0573
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13 hours ago, Tarun Khubchandani said:

Hey All!

I just wanted to check, if a question asks us to integrate a function using integration by parts, do I strictly need to follow the formula booklet's formula for integration by parts, or may I use (the significantly faster) tabular integration by parts method? Also, does anyone have any specific tips on deciding whether to integrate a function by parts or use u-substitution?

Thanks in advance!

Integration by parts? Never came across that. Is it HL?

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5 minutes ago, ultimateone said:

Integration by parts? Never came across that. Is it HL?

Yes it is HL. This is after all, HL & Further subforum. 

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1 minute ago, kw0573 said:

Yes it is HL. This is after all, HL & Further subforum. 

Ah yes, didn't notice that, sorry! I just saw it on the home page of the site.

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We were Never taught the Tabular method, so I just stay strictly to the formula booklet, after all, it is like a bible to me. HAHA

 

Any advice for a confidence booster?

 

 

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4 hours ago, Stewart.M said:

We were Never taught the Tabular method, so I just stay strictly to the formula booklet, after all, it is like a bible to me. HAHA

 

Any advice for a confidence booster?

 

 

Same, the formula booklet is a life saver! 

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58 minutes ago, ibstudent081099 said:

Same, the formula booklet is a life saver! 

Seriously ?? I rarely use the formula booklet (expect sometime when I am too lazy to integral/differentiate standard functions) 

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9 minutes ago, Haitham Wahid said:

Seriously ?? I rarely use the formula booklet (expect sometime when I am too lazy to integral/differentiate standard functions) 

When I am stuck I go through the booklet and the majority of times I find the solution. Btw I am so worried for maths!!! (I need a 7)

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2 minutes ago, ibstudent081099 said:

When I am stuck I go through the booklet and the majority of times I find the solution. Btw I am so worried for maths!!! (I need a 7)

I understand what you mean! Well try to do as many exam questions as possible, specially on topics you feel weak at. For example,  I had trouble with plane intersections but after doing hundreds of questions on this part of the syllabus they now seem very easy. So just keep on practising until the exam starts. Good luck!  

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21 minutes ago, Haitham Wahid said:

I understand what you mean! Well try to do as many exam questions as possible, specially on topics you feel weak at. For example,  I had trouble with plane intersections but after doing hundreds of questions on this part of the syllabus they now seem very easy. So just keep on practising until the exam starts. Good luck!  

Yeah doing past papers is the best solution. 

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