# integration

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#1
integrate between L and -L :
sin(m.pi.x/L)sin(n.pi.x/L)
to show it = 0

i can do it for cos because wen u integrate cos u get sin and all multiples of pi are 0. but for cos the multiples of pi are eitha 1 or -1

can someone show me explicitly how to do this
0
15 years ago
#2
Could you just say that because you're integrating between -L and L, and as sin is an odd function, that the integral must be zero as the positive portion will exactly cancel the negative one?
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#3
unfortunately not ive actually got to do the integral
0
15 years ago
#4
couldnt do it but heres it in LaTeX form.. I'm practicing
0
15 years ago
#5
Expand Cos(A+B) and Cos(A-B) to find an expression for Sin(A)Sin(B), then apply this to your question.
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