How can I plot this exponential decaying sinusoid

y(x) = F * exp^(-a*x) * sin(bx)

pick you own values for x vector.

value of a and b:

ethyl alcohol 0.246 0.806

water 0.250 1.000

Oil 0.643 1.213

plot using the values above for each fluid.

Here is a portion of my approach.

extf = input('Please enter the magnitude of the external force: ');

yethylalchol == extf*exp(-0.246*x).*sin(0.806*x);

plot( x,yethylalcohol,'c*' )

hold on

ywater == extf*exp(-0.250*x).*sin(1*x);

plot( x,ywater,'r+' )

hold on

yoil == extf*exp(-0.643*x).*sin(1.213*x);

plot( x,yoil, 'yp')

What am I doing wrong? Help please!!!

Answer 1

[Mischa Kim]

Nabin, how about

 % value of a and b:
 % ethyl alcohol 0.246 0.806
 % water 0.250 1.000
 % Oil 0.643 1.213

 F = 1;
 x = 0:0.1:2*pi;
 a = [0.246 0.250 0.643]';
 b = [0.806 1.000 1.216]';
 y = F * exp(-a*x).*sin(b*x);
 plot(x,y)

Answer 2

[Nabin SUNAM]

Thanks Miscah for the try. I tried to run this script and this is the message I'm getting.

"Error using *

Inner matrix dimensions must agree."

I wonder what it means.

[Mischa Kim]

Nabin, did you re-type the script (as opposed to doing a copy-paste)? You might have missed a dot or prime.