# Matlab help a noob

1. Jan 25, 2006

### dervast

Hi there.. I am really noob to matlab i want to draw the following equation
P(L)=Po*e^(-aL)
How can i draw this function?
Can u help me?
L takes values from 0 to 10km
a=0.2db/km
and Po=1watt

2. Jan 26, 2006

### hypnagogue

Staff Emeritus

3. Jan 27, 2006

Code (Text):
Po = 1; % define Po
a = 0.2; % define a
L = 0:10/100:10 % make a vector L with 100 elements evenly spaced from 0 to 10

%option 1, compute P(L) one element at a time
for i = 1:length(L) %loop through all values of L
P1(i) = Po*exp(-a*L(i));
end

%option 2, compute all the values at once
P2 = Po*exp(-a*L);

figure;plot(L,P1) % Plot P vs L