How do I plot this vector curve?

3 views (last 30 days)
Jason Shu
Jason Shu on 19 Oct 2017
Edited: Cam Salzberger on 19 Oct 2017
Very new to matlab, still learning.
How do i plot the curve parametrized by P(t) = (1 - cos t)i + (1 + 2t + t^2)j for 0<=t<=1?
I have tried
x=linspace(-1,1)
i = 1 - cos(t)
j= 1 + 2*t + t.^2
plot(x,i,x,j)
but it says "Vectors must be the same length." Any idea what I'm doing wrong here?

Accepted Answer

Cam Salzberger
Cam Salzberger on 19 Oct 2017
Edited: Cam Salzberger on 19 Oct 2017
Hello Jason,
"(1-cos(t))i" means that this point will be at the x-coordinate "1-cos(t)" for time t. Similarly for "j" -> y-coordinate. So you're on the right track, but the trick is to know that MATLAB doesn't care what time it is while plotting. It only wants to know the x and y coordinates.
t = linspace(-1, 1, 10);
x = 1 - cos(t);
y = 1 + 2*t + t.^2;
plot(x, y)
The error was likely because you were defining "x" instead of "t" in the first line, but you had an existing "t" value left over from before. Be careful about that when writing scripts.
Also, I'd recommend against using "i" or "j" as variable names in MATLAB, since they have a built-in meaning as the imaginary unit.
-Cam

More Answers (0)

Categories

Find more on Fit Postprocessing in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!