MATLAB: Hey! I am new to matlab and I need some help here.

homeworkprogramming

So this is the problem: Write an equation that plots the quadratic formula, linearly spaced with 100 divisions. The equation for a particular quadratic expression should be in the form ax^2 +b^x + c,with the bounds on x are x1 and x2 where i t is assumed that x1 < x2. Using the functions linspace and plot may prove to be helpful as well as the hold switch. Make sure you include a title on the plot.
ANY HELP would be really appreciated!

Best Answer

% Let's say:
a=3;
b=2;
c=1;
% we have y= ax^2 + bx + c;
% so the function to plot would be y=3x^2+2x+1;
p=[a, b, c];
% now let's say:
x1=-10;
x2=10;
n=100; %number of samples
x=linspace(x1,x2,n);
y=polyval(p,x);
plot(x,y)
title(sprintf('y= %fx^2 + %fx + %f',p(1),p(2),p(3)))
You can write that in function form as follows:
function myPlot(a,b,c,x1,x2,n)
  p=[a, b, c];
  x=linspace(x1,x2,n);
  y=polyval(p,x);
    plot(x,y)
    title(sprintf('y= %fx^2 + %fx + %f',p))
  end
Now you can call it as follow
myPlot(3,2,1,-10,10,100);
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