plot error

I am trying to do

 t=0:0.001:10;
 plot(0.25*exp(-t)*sin(2*t),t)

and it says:

 ??? Error using ==> mtimes
 Inner matrix dimensions must agree.

When I tried to divide by exp(t) instead it gave me crap. any ideas? thanks

Answer 1

[Sean de Wolski]

t=0:0.001:10; 
plot(0.25*exp(-t).*sin(2*t),t)

You want an element by element multiplication so you need the '.' in front of the '*'

[Arnaud Miege]

You typed quicker than me :-)

Answer 2

[Arnaud Miege]

You need to use element-wise operating rather matrix opertaions. Read about Arithmetic Operators in the MATLAB documentation.

HTH,

Arnaud

Answer 3

[Daniel Shub]

size(exp(-t))
size(sin(2*t))

You are trying to multiple a 1x1001 matrix with a 1x1001 matrix. The inner dimension (1001 and 1) do not match. Try .*

plot(0.25*exp(-t).*sin(2*t),t)

Answer 4

[Anthony Smith]

Matlab is always thinking in terms of matrices. Therefore you would want to use element-by-element multiplication (.* instead of *) to generate your simple function in this case.

Try:

t=0:0.001:10; plot(t,0.25*exp(-t).*sin(2*t))

Answer 5

[hagai bar]

thanks everyone