Colors in the legend do not match the plot
I need to build several Maclaurin series and I am having legend issues.
For these two equations -
x = (-1:.01:1);
% e^x
eqtn21 = 1;
eqtn22 = 1 + x;
eqtn23 = 1 + x + x.^2/2;
eqtn24 = 1 + x + x.^2/2 + x.^3/6;
eqtn25 = exp(x);
% cos(x)
eqtn31 = 1;
eqtn32 = 1 - x.^2/2;
eqtn33 = 1 - x.^2/2 + x.^4/24;
eqtn34 = 1 - x.^2/2 + x.^4/24 - x.^6/720;
eqtn35 = cos(x);
subplot(2,2,1)
plot(x,eqtn21,'r',x,eqtn22,'g',x,eqtn23,'b',x,eqtn24,'k',x,eqtn25,'c')
legend('First Term','First Two Terms','First Three Terms','First Four Terms','Exact Function')
subplot(2,2,2)
plot(x,eqtn31,'r',x,eqtn32,'g',x,eqtn33,'b',x,eqtn34,'k',x,eqtn35,'c')
legend('First Term','First Two Terms','First Three Terms','First Four Terms','Exact Function')
When I draw them, the legend appears but shows 5 red lines and doesn't match the colors in the graph.
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The problem is related to eqtn21
and eqtn31
. They have a size of 1, and x
a vector of a different size. When you draw, you need to match their dimensions to size x
if you want to have a constant string (so for all x values, you get 1) oreqtn21 = [1 1 1 1 ... 1];
An easy way to do this is to write eqtn21 = 1+0*x;
, etc. Other ways to do this can be modified eqtn21
with repmat
or by matrix multiplication, etc ...
eqtn21=repmat(1,[1 numel(x)])
or
eqtn21=1*ones(1,numel(x))
etc...
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