Integration by substitution Q

Q: ∫1+sinx/cosx dx ; u = sin x

I can't get it into something that i can integrate..

I get upto ∫1+u/1-u² but i'm stuck on what to do next, can someone help me please?

Reply 1

TomX

14

Try splitting it into int(1/(1-u^2) + int(u/(1-u^2))

Sorry for the untidyness of the maths above, I'll read the FAQ on doing maths symbols.

Reply 2

m:)ckel

14

Tom, are you using the Quick reply box? If so, click 'Reply' (in the post bit) or 'Go advanced' in the quick reply box, and you'll see a full set of Maths symbols. =)

Btw, I would've thought it's easier just to say (1-u²) = (1+u)(1-u), and cancel the (1+u) term.

Reply 3

TomX

14

mockel

Tom, are you using the Quick reply box? If so, click 'Reply' (in the post bit) or 'Go advanced' in the quick reply box, and you'll see a full set of Maths symbols. =)

Btw, I would've thought it's easier just to say (1-u²) = (1+u)(1-u), and cancel the (1+u) term.

Yeah that probably would be easier, oh well :P

I thought: arctan u + ln(1-u²)/2 + c was a little complicated, it's probably wrong too.

Thanks for the tip on doing maths symbols.

Reply 4

violet

OP

2

mockel

Tom, are you using the Quick reply box? If so, click 'Reply' (in the post bit) or 'Go advanced' in the quick reply box, and you'll see a full set of Maths symbols. =)

Btw, I would've thought it's easier just to say (1-u²) = (1+u)(1-u), and cancel the (1+u) term.

Oh yeh, that works.. Thanks.... again!
I need to train my brain to work like yours :rolleyes:

Integration by substitution Q

Related discussions

Latest

Trending

Trending

Articles for you