Ah ok, jumped the gun a bit then. Was this an exam Q or just out of interest?
This was a june 2014 exam question (6iii). Since then, I've encountered a similar situation in third party practice paper where the solution was less obvious that in the 2014 Q, but integration by parts was an option. I'm just interested since a universal method is less of a headache and saves time.
This was a june 2014 exam question (6iii). Since then, I've encountered a similar situation in third party practice paper where the solution was less obvious that in the 2014 Q, but integration by parts was an option. I'm just interested since a universal method is less of a headache and saves time.
wonder how they marked those who went for above approach. I'd like to think if they pulled something like that in an edexcel paper they would at least point you in the direction of what to do.
wonder how they marked those who went for above approach. I'd like to think if they pulled something like that in an edexcel paper they would at least point you in the direction of what to do.
I just don't know what I'm missing. Two questions where integration by parts seems impossible say " integration by parts twice" in the notes, and magically arrive at the solution.
I just don't know what I'm missing. Two questions where integration by parts seems impossible say " integration by parts twice" in the notes, and magically arrive at the solution.
Care to post a link? Seems silly to prevent someone from doing it in the simplest way
Tbf, looking at the edexcel mark scheme it seems they are not being picky as to what method you apply - 1 method mark for double angle formula and then 1 method mark for 'integrating to give asin^3 x. I can't seem to open the mark scheme for the other exam but looking at the question i cant find much which specifies a certain way in which to attack the integral. Would still like to see a worked example of integration by parts for it though, even if it is just out of interest
How do you integrate a product such as Sin2xSinx by parts? Apparently this can be done but I don't see how you can avoid an endless loop. Many thanks
I left out all the "dx" to save space but I hope it's clear - after doing by parts twice you get the same integral as you started with as part of your integration and you make that the subject of the formula.
I left out all the "dx" to save space but I hope it's clear - after doing by parts twice you get the same integral as you started with as part of your integration and you make that the subject of the formula.
Hmm didn't know they expected you to know the integration by parts twice method and using the loop to substitute the original back in.
I knew how to do that but my teacher said they wouldn't specifically require you to do that - so you could do questions like that but they would only ask a question that could be done without that method also.
Hmm didn't know they expected you to know the integration by parts twice method and using the loop to substitute the original back in.
I knew how to do that but my teacher said they wouldn't specifically require you to do that - so you could do questions like that but they would only ask a question that could be done without that method also.
Well I know that integration by parts twice could come up definitely as I have seen it on a paper.It's good to know.