How multiply cos and sin (eg. cos(pi*x).*sin(pi*y))

Hi All,

I have a value for out1 using the below code

out1=double(int(int((exp(x+y)*cos(pi*x)*cos(pi*y)),x,-1,1),y,-1,1))

I would like to multiply cos(pi*x).*sin(pi*y)) by out1 by passing the same range for x and y.

My code is like below

out1=double(int(int((exp(x+y)*cos(pi*x)*cos(pi*y)),x,-1,1),y,-1,1)) 
answer1=cos(pi*x).*sin(pi*y)
answer2 = out1.*answer1

I am getting the below error,

Error using  * 
Inner matrix dimensions must agree.

Thanks,

With regards,

GK.Jagatheswari

Answer 1

[Image Analyst]

Are x and y arrays? Or scalars in a loop?

whos x
whos y

What does it report in the command window? It seems like they're arrays, and it so you must use .* instead of * before the cos()

out1=double(int(int((exp(x+y)  .* cos(pi*x) .* cos(pi*y)),x,-1,1),y,-1,1))

because you're multiplying an array by an array element-by-element. Otherwise it will do a matrix multiplication and you'll get an error message like that.

[jagatheswari kathirvel]

Hi, There is no problem in evaluating out1. I got the answer. Again with out1, I want to multiply cos(pi*x) and cos(pi*y), because that is the definition of fourier sereis in two dimension.Iam getting an error message saying that Error using * Inner matrix dimensions must agree..Please help. Otherwise is there any direct way to multiply cos(pi*x) and cos(pi*y) with b1.

[Image Analyst]

Give the exact error message. Quit snipping out just a part of it. Post ALL the red text, line number, everything .