integration

[refid]

Can someone help me on this question

S e^(-3X)cos(pi/2 X)


i started with

Dv=cos(pi/2X) u=e^(-3X)

v=(2/pi )sin(pi/2X) du= -3e^(-3X)dx

then ...... uv - S vdu

e^(-3X)(2/pi )sin(pi/2X) - S (2/pi )sin(pi/2X) -3e^(-3X)dx

e^(-3X)(2/pi )sin(pi/2X) + 3(2/pi ) S sin(pi/2X) e^(-3X)dx

im stuck after this part ^

 

[stapel]

Do you mean the following?


. . . . .\(\displaystyle \large{\int{\.e^{-3x}\,\cos{(\frac{\pi}{2}\,x)}\,}dx}\)


Thank you.

Eliz.

 

[tkhunny]

You seem to be on the right track. Do it again with the remaining itegral expression and something will pop up. Trussssssst me....

 

[Daniel_Feldman]

Can someone help me on this question

S e^(-3X)cos(pi/2 X)


i started with

Dv=cos(pi/2X) u=e^(-3X)

v=(2/pi )sin(pi/2X) du= -3e^(-3X)dx

then ...... uv - S vdu

e^(-3X)(2/pi )sin(pi/2X) - S (2/pi )sin(pi/2X) -3e^(-3X)dx

e^(-3X)(2/pi )sin(pi/2X) + 3(2/pi ) S sin(pi/2X) e^(-3X)dx

im stuck after this part ^

Now, let u=(6/pi)e^(-3x) and dv=sin((pi/2)x)dx

Do integration by parts again and see where you are.