f(x) = cosax between pi and -pi and a is a constant

can find the an coefficent to be (sin(n+a)x)/(n+a) + (sin(n-a)x)/(n-a) but cant get any further.

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- May 11th 2010, 05:18 PMdanniefourier series representation
f(x) = cosax between pi and -pi and a is a constant

can find the an coefficent to be (sin(n+a)x)/(n+a) + (sin(n-a)x)/(n-a) but cant get any further. - May 12th 2010, 03:44 AMHallsofIvy
This makes no sense. The coefficient can't be a function of x. Did you forget to evaluate at and ?

cos(ax) is an even function- it will have**no**"sin(nx)" terms in it. The coefficient of cos(nx) will be

for n> 0.

The n= 0 term is .

As I said above, all coefficients of "sin(nx)" will be 0. - May 12th 2010, 12:40 PMAllanCuz