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Homework Statement
Evaluate
integral sin^(-3/2)(x)cos^3(x) dx
Homework Equations
tan(x)=sin(x)/cos(x)
sin^2(x)+cos^2(x)=1
sin^2(x)=(1-cos(x))/2
cos^2(x)=(1+cos(2x))/2
integral cos(x)dx = sin(x) + c
integral sin(x)dx = -cos(x) + c
d/dx sin(x) = cos(x)
d/dx cos(x) = -sin(x)
a^m/a^n=a^(m-n)
a^m*a^n=a^(m+n)
sin(x)=(e^(ix)-e^(-ix))/(2i)
cos(x)=(e^(ix)+e^(-ix))/2
tan(x)=sin(x)/cos(x)
cis(x)=cos(x)+i*sin(x)=e^(ix)
cis(-x)=cos(x)-i*sin(x)=e^(-ix)
e^(i*pi)+1=0
The Attempt at a Solution
I'm at a lost as to how even to being...
I tried using sin^2(x)+cos^2(x)=1
I tried using some of the double angle formulas
every single time I get to the point were I don't know how to proceed
MATLAB answer:
>> int(cos(x)^3/sin(x)^(3/2))
Warning: Explicit integral could not be found.
ans =
int(cos(x)^3/sin(x)^(3/2), x)
Wolfram Alpha answer:
-40/9 F(1/4 (pi-2 x)|2)-2/9 sqrt(sin(x)) (2 cos(x)+3 x (sin(x)+3 csc(x)))+constant
My answer:
Don't even know how to proceed after a couple of steps
Back of the book:
Only odd answers are given... this is problem #16
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