Hello,(adsbygoogle = window.adsbygoogle || []).push({});

Say I'm working with ∫ sqrt(1-cos(t)) dt

I end up with a substitution of u = 1-cos(t) and dt = du/sin(t)

sub back in: ∫ sqrt(u) / sin(t) du

Still got a t in there ... hrrmmm

So I go to wolfram alpha for some inspiration and 'show steps':

http://www.wolframalpha.com/input/?i=integrate++sqrt(1-cos(t))

After some bashing about I see what they are doing is valid - but have no idea how to go aboutspottingwhat they have done in between the substitution and ending up with an integral only in terms of u.

I need a little sub-'show-working' section - anyone care to show me how the 'ah-hah, that'll work!' moment actually comes about ?

It's simple ?

regards,

N

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Help spotting trig identities to simplify integration

**Physics Forums | Science Articles, Homework Help, Discussion**