March 22nd, 2008, 10:22 AM  #1 
Newbie Joined: Feb 2008 Posts: 16 Thanks: 0  integral evaluation....
int (sin3x*sin5x)dx=?

March 23rd, 2008, 10:55 AM  #2 
Member Joined: Dec 2007 Posts: 30 Thanks: 0 
notice that: sinA*sinB=1/2[cos(A+B)cos(AB)] and cos2x= 12(sinx)^2 ıntegral becomes: 1/2 S[cos(8x)cos(2x)]dx = 1/2[sin8x/8  sin2x/2] +C 

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evaluation, integral 
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