Matlab）如何用各种输入参数绘制函数图？

Question

mfunction.m

function[P] = mfunction(v,M,R,T)
P=4*pi*(M/(2*pi*R*T)).^(3/2)*v.^2*exp((-M*(v.^2))/(2*R*T));
end

I want to make a graph. x would be v and the range is 1: 1200 ,

M = 0.032,R = 8.31, T= 300 

and I want to plot y=mfunction(x)

and errors pop up. How can I draw a graph?

Answer 1

The problem lies at the middle multiplication

P=4*pi*(M/(2*pi*R*T)).^(3/2)*v.^2  *   exp((-M*(v.^2))/(2*R*T));
                                   ^

What you are doing is similar to doing

[1,2] * [1,2]

, which gives you the error "mtimes Inner matrix dimensions must agree", because it is multiplying a mx1 matrix to an mx1 matrix.

Depending on want you need, you can do one of the following:

>> [1,2] * [1,2]'  %inner product

ans =

     5

>> [1,2]' * [1,2]

ans =

     1     2
     2     4

>> [1,2] .* [1,2]  %element-wise product

ans =

     1     4