# Plotting a function given a range of inputs

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Jesse Green on 6 Mar 2018
Commented: Vatsal Dhamelia on 11 May 2020
I need to plot a line of the Moody chart given a relative roughness and range of Reynolds numbers but I have no clue how to write a plot code. For simplicity, lets say I want to plot y=8x+10 with a range of 2<x<20. How would I go about doing this? Thank you.

Elias Gule on 6 Mar 2018
First define your vector x as:
dx = 0.01;
x = 2:dx:20; % where dx in the increment from one x value to the other.
OR
N = 40; % number of samples
x = linspace(2,20,N);
then define y as:
y = 8*x + 10;
Then to plot:
plot(x,y);
For more help please look at the VERY USEFUL Matlab documentation. In the command window just type:
doc plot
##### 2 CommentsShow 1 older commentHide 1 older comment
Vatsal Dhamelia on 11 May 2020

Star Strider on 6 Mar 2018
One possibility:
x = linspace(2, 20, 25);
y = 8*x + 10;
figure(1)
plot(x, y, '-pg')
grid
xlabel('x')
ylabel('y')
title('Moody Chart')
See the documentation for the various functions for details on their uses.