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fortheloveofscience Group TitleBest ResponseYou've already chosen the best response.0
\[\int\limits_{0}^{\Pi/2} \sin ^{2}x \div (\sin ^{2}x+4\cos ^{2}x)\]
 2 years ago

perl Group TitleBest ResponseYou've already chosen the best response.1
change cos^2 = 1  sin^2
 2 years ago

perl Group TitleBest ResponseYou've already chosen the best response.1
so you have for the denominator sin^2 + 4(1sin^2) = sin^2 + 4  4 sin^2 3sin^2 + 4
 2 years ago

shankvee\ Group TitleBest ResponseYou've already chosen the best response.0
I think this is aprtial fractions. If you take cos^2 x common from denominator you have tan^2 x/(tan^2 x+4) Put tan x=t. you'll get dx=dt/sec^2 x= dt/(1+t^2). So you have t^2/((t^2+4)(t^2+1)). Do you know partial fractions?
 2 years ago

perl Group TitleBest ResponseYou've already chosen the best response.1
you dont need partional fractions
 2 years ago

shankvee\ Group TitleBest ResponseYou've already chosen the best response.0
How will you do it by converting denominator to sin?
 2 years ago

perl Group TitleBest ResponseYou've already chosen the best response.1
the denominator is 3sin^2 t + 4 , do long division
 2 years ago

fortheloveofscience Group TitleBest ResponseYou've already chosen the best response.0
we gottta use the properties of definite integrals
 2 years ago

perl Group TitleBest ResponseYou've already chosen the best response.1
shank, change cos^2 = 1  sin^2
 2 years ago

shankvee\ Group TitleBest ResponseYou've already chosen the best response.0
And then what?
 2 years ago

perl Group TitleBest ResponseYou've already chosen the best response.1
dw:1328867815825:dw
 2 years ago

shankvee\ Group TitleBest ResponseYou've already chosen the best response.0
You're effectively doing the same thing only.
 2 years ago

perl Group TitleBest ResponseYou've already chosen the best response.1
dw:1328867933423:dw
 2 years ago

shankvee\ Group TitleBest ResponseYou've already chosen the best response.0
By doing by partial fractions it reduces to the same thing. Only it is in terms of t^2 so easier to integrate. You directly get tan inverse form which is easy.
 2 years ago

perl Group TitleBest ResponseYou've already chosen the best response.1
ok you did trig substitution
 2 years ago

shankvee\ Group TitleBest ResponseYou've already chosen the best response.0
For the second term you divide by cos ^2 and then you get tan form and then you put that as t to integrate, You get that directly by partial fractions in terms of t.
 2 years ago

perl Group TitleBest ResponseYou've already chosen the best response.1
i see that, im asking about your t = tan x part
 2 years ago

perl Group TitleBest ResponseYou've already chosen the best response.1
what sort of substitution is this called?
 2 years ago

shankvee\ Group TitleBest ResponseYou've already chosen the best response.0
Yeah thats a trignometric substituion.
 2 years ago

perl Group TitleBest ResponseYou've already chosen the best response.1
ok your solution is better, im not sure if i would go ahead with mine . not sure what do do next
 2 years ago

perl Group TitleBest ResponseYou've already chosen the best response.1
you can divide top and bottom by cos^2 for my solution
 2 years ago

perl Group TitleBest ResponseYou've already chosen the best response.1
shank, can i ask a simple question about kites
 2 years ago
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