How to plot a simple function that has a variable?

2018 11 16
3 个回答
回答已采纳
更新时间：2018 12 9
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0 个投票

The question I have is:
Write a MATLAB function
func(x,a) = x^2 + ax - 6
Use the function to plot, func(x,1), func(x,2) and func(x,3) on the same axes, for -10<x<10.
Im really confused how to define a as 1, 2 and 3 and how to substitute them into the function.

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 采纳的回答

madhan ravi
madhan ravi 2018-11-16
编辑：madhan ravi 2018-11-16

0 个投票

Read about fplot()
syms x
for a=1:3
func = x^2 + a*x - 6 ;
fplot(func,[-10 10]) %ranging from -10 to 10
hold on
end
Screen Shot 2018-11-16 at 8.00.07 PM.png

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Stephen23
Stephen23 2018-12-9
编辑：Stephen23 2018-12-9
I very much doubt that this assignment was intended to require the Symbolic Toolbox. The assignment "Write a MATLAB function ..." requested an actual MATLAB function:
https://www.mathworks.com/help/matlab/functions.html
and this is what the other answers provide.

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更多回答（2 个）

TADA
TADA 2018-11-16

0 个投票

func = @(x,a) x^2 + a*x - 6;
x = -10:0.1:10;
for a = 1:3
plot(x, func(x,a ));
hold on;
end
Stephen23
Stephen23 2018-11-16

0 个投票

You can do this very simply by defining a normal function handle:
>> F = @(x,a) x.^2 + a*x - 6;
>> X = -10:.1:10;
>> plot(X,F(X,1),'r', X,F(X,2),'g', X,F(X,3),'b')
F.png

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