Ask your own question, for FREE!
Mathematics 9 Online
OpenStudy (anonymous):

having trouble with trig substitution integrals.

OpenStudy (anonymous):

What is the problem?

OpenStudy (anonymous):

The question is meant to help me, but I've been having trouble understanding the lecture. Here is the question:

OpenStudy (anonymous):

I'm sorry I couldn't type it out, but it's on a website :/

OpenStudy (aravindg):

the dirst thing is that you should be thorough with you trigonometry then only the correct substitution will strike you

OpenStudy (aravindg):

*first

OpenStudy (anonymous):

I know a decent amount of trig.... I know that I need to use arctan for this substitution.

OpenStudy (anonymous):

or tan... sorry.

OpenStudy (anonymous):

g(t) = sqrt(1+(6t-7)^2)? Haven't taken this calculus in a while.

OpenStudy (anonymous):

How did you get that? I had set x=tan(6t-7), but I was stuck after that.

OpenStudy (anonymous):

you want to get the original equation to be simplified. so 1/g(t) where g(t) = another function which can be integrated?

OpenStudy (anonymous):

...Where are we getting tan from?

hartnn (hartnn):

so that u get 1+ tan^2 t in square root sign

hartnn (hartnn):

so that u get sec t in denominator

hartnn (hartnn):

so that u get cos t in numerator

OpenStudy (anonymous):

Ah okay I see, your using an identity. Okay.

hartnn (hartnn):

f(t) = cos t

OpenStudy (anonymous):

I'm sorry, but I'm still a bit confused about what I'm doing :/. am I still using x=tan(6t-7)? My apologies, but it's all very new to me.

hartnn (hartnn):

u want 1+tan^2 t under square root sign so that u can write it as sec^2 t ......ok? now u had (6x-7)^2 to make it tan^2 t u put 6x-7 = tan t or 6x=tan t +7 or x = (tan t +7) / 6 = g(t) got this ?

OpenStudy (anonymous):

ah ok I think I understand now. Thank you.

hartnn (hartnn):

glad to help ^_^

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!