# How to edit properties of a plot and highlight certain points in the graph at the same time?

16 views (last 30 days)
theblueeyeswhitedragon on 7 Oct 2017
Answered: Kian Azami on 7 Oct 2017
This is the code I wrote for graphing the Phase Plot of the differential equation dy/dt = y(y-2)(y-2)(y-4)(y-6),
but I am getting errors for this line of the code:plot(y, yPrime, 'Color', 'Red', 'LineWidth', 2, eqPoints, zerosVec, 'k*');
Complete Code:
%%Phase Plot
y = -1 : 0.01 : 7; %define the values of y
yPrime = y.*((y-2).^2).*(y-4).*(y-6); %differential equation
eqPoints = roots([1 -14 68 -136 96 0]); %find the critical points
zerosVec = zeros(length(eqPoints), 1); %create a zeros vector with length equal to the number of roots of the polynomial
plot(y, yPrime, 'Color', 'Red', 'LineWidth', 2, eqPoints, zerosVec, 'k*');
xlabel('y');
ylabel('dy/dt');
title('Phase Plot');

Kian Azami on 7 Oct 2017
Mario you are using a wrong command for highlighting your points. Just you need a very small change to highlight the points as follow (if I understood correctly):
plot(y, yPrime, 'Color', 'r', 'LineWidth', 2)
hold on
plot(eqPoints, zerosVec, 'k*')