How to Plot a 4th Degree Polynomial in MATLAB: Step-by-Step Guide

[saeede-]

hey everyone . I want to plot a Grade 4 equation in MATLAB. but don't know how to do. Can anyone guide me?

equation : f = 1.47*(x^4)-10^7*(x)+58.92*(10^6)

 

[Orodruin]

If your x is a row/column matrix you will need to add a . before multiplicative operations to make them element-by-element. In other words, if you have something like

x = 0:0.01:10;

then you will need to do

f = 1.47*(x.^4)-10^7*(x)+58.92*(10^6)

because Matlab does not understand what a row/column matrix to the power of 4 means.

 

[jedishrfu]

The dot operator is something often missed by newbies to matlab.

 

[Mark44]

hey everyone . I want to plot a Grade 4 equation in MATLAB. but don't know how to do. Can anyone guide me?

equation : f = 1.47*(x^4)-10^7*(x)+58.92*(10^6)

Your post confused me -- I thought this might be an equation given to someone in the fourth grade. In English we call such equations fourth degree, not Grade 4.

 

[Mark44]

If your x is a row/column matrix you will need to add a . before multiplicative operations to make them element-by-element.

I suspect, without much evidence, that the OP merely wants to graph the equation, where x is a real number.

 

[Orodruin]

I suspect, without much evidence, that the OP merely wants to graph the equation, where x is a real number.

Yes, and the typical way to do that in MATLAB is to first create a vector x containing the x values, then using a function as described above to get the corresponding y-values. Then using the MATLAB plot function, which takes the vectors of x and y values as input. This is why you need the dot in the operator in the second step.

 

[jedishrfu]

[CODE lang="matlab" title="Plot example"]x = [0:100]
y = x .* x
plot(x,y)[/CODE]

Also there is a nice MATLAB clone called Freemat which supports the core functionality of MATLAB.

http://freemat.sourceforge.net/

 

[saeede-]

Your post confused me -- I thought this might be an equation given to someone in the fourth grade. In English we call such equations fourth degree, not Grade 4.

yes I'm not an English person . so it's normal having such mistakes.