# evaluating functions and plotting

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sumaiya hossain on 5 Aug 2022
Commented: sumaiya hossain on 5 Aug 2022
evaluate and plot: What I did for this question was I put each of the equations into a variable : eqn, eqn2 , eqn3 then from that I substituted the x values that apply to each equation and saved it as a , b , c. However I am unsure to how I would plot the graph into one as they are saved as 3 different variables.
First I assumed I would have to plot each graph separately but I am unsure if that is correct or not.
can I get some advice if plotting 3 different graphs for each variable is reasonable or there is another approach I should take.
syms x
eqn = 2*x^2
eqn = a = subs(eqn,x,(0<x)&(1>=x));
eqn2 = x^2 + 3
eqn2 = b = subs(eqn2,x,(1<x)&(3>=x))
b = eqn3 = -3*x
eqn3 = c = subs(eqn3,x,(3<x)&(5>=x))
c = Torsten on 5 Aug 2022
Use "piecewise" if you want to work with symbolic variables and functions.
Otherwise
f = @(x)2*x.^2.*(x>0 &x<=1) + (x.^2+3).*(x>1&x<=3) + (-3*x).*(x>3&x<=5);
x = 0:0.01:5;
plot(x,f(x)) sumaiya hossain on 5 Aug 2022
Thank you! Yes i was unsure if you could actully plot it together, I understand now. :)

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