Maths wtf

[meghatronic]

,.

 

[meghatronic]

I can count to potato!

I can only count to pancake without help

 

[meghatronic]

A level maths, making me feel retarded since 2003.

Interesting year. I messed up my A level Maths in 2003.... (failed)

Trying to make amends.

 

[meghatronic]

The constant is Desmond remember.

 

[meghatronic]

 

[meghatronic]

Well for a start that result needs simplifying; it should be 2*sqrt(arcsin(x)). As for the integral, just make the substitution x = sin(u) and it all drops out nicely:

Who's awesome? You're awesome.

I completely forgot about integration by substitution.....

Only sad people post mathematics equations at 2:35 in the morning and expect a proper answer.

I wasn't bothered by the faux posts - it's what makes OcUK great.

Is it just me or does this stuff just fall out of your head as soon as you stop using it on a daily basis?

Evidently, yes!

 

[meghatronic]

I did maths and further maths A level (a grades) and maths at University and I can't supply an answer (although the answer posted did make sense)

Amazing how much stuff you forget.

Worrying, really. 1/3 of my degree was Chemistry, and a friend of a friend asked the other day for me to check over some of their A level coursework. I didn't have a ****** clue. That £14k was well spent.....!

 

[meghatronic]

1/sqrt((1 - x^2)) is a very common one to watch out for with trig substitutions.

Here you easily get rid of the arccsc by subtituting x = sinu, and then the rooted bracket simplifies nicely to an easy integration.

The thing that was greatly frustrating me is I was obsessing over the differential of 1/sqrt((1 - x^2)) is arcsin x +c, but could then not see how this fitted in the puzzle! Doh.

Although I'm trying to work out how 1/ becomes cos u/ at the moment

 

[meghatronic]

When you subsitute:
x = sinu
dx/du = cosu
dx = cosu du

so dx is exchanged with cosu du

I just read up on integration by substitution, I like the fact one can treat "dx" as an entity. Seems cheeky

I owe lots of cookies today!

 

[meghatronic]

Substitute in and voila!

EDIT: Damnit, beaten again

Like a ginger stepchild.

Threads like this remind me:
(1) I'm not alone in forgetting things,
(2) There are always people better than you,
(3) There are always people willing to help for no gain,
(4) OcUK is a great community
and
(5) pancake.