Getting the Incorrect Plot

I have a function (func) given to me with desired x-values (x). The assignment is to plot func while also plotting the x-intercepts. It appears to me that I am getting the correct values when I check the x/y data points, but the graph does not line up.

x = -10:.1:8;
func = (x-6).*((x.^2)-1).*(x+8);

plot(func);
title("Graph of Function");
xlabel("Vector Values");
ylabel("Function Values");
hold on;

%Plots the x-intercepts
[~,cols] = size(func);
for i=1:cols 
    if func(i) == 0
        plot(x(i),0,'*r')
    end
end

The x-intercepts are correct and the data points are correct; however, my plot does not line up. Not sure what is wrong. Any help would be great!

Answer 1

[Kevin Phung]

x = -10:.1:8;
func = (x-6).*((x.^2)-1).*(x+8);
plot(x,func);
title("Graph of Function");
xlabel("Vector Values");
ylabel("Function Values");
hold on;
%Plots the x-intercepts
indx = find(func==0);
plot(x(indx),zeros(1,numel(indx)),'*')

edit: what went wrong is that you didnt plot(x,func) in the beginning, so the scaling of the x axis was different.

[Jonathan Fletcher]

Wow. I can't tell you how long I have been looking at that for. Thanks!

Answer 2

[Ahmed Abuelgasim]

Guys,

In my below code, x-axis doesn't type or show the correct vaules. please your support.

x=[x,LTE_1_RSRP]; 
 y=[y,LTE_2_RSRP]; 
plot (x, 'r-', 'linewidth', 3);hold on 
plot (y, 'g-', 'linewidth', 3);hold on 
grid minor
xlabel('RSRP of LTE Cell One')
ylabel('RSRP of LTE Cell Two')
title('RSRP Varition in LTE Cells')
legend('RSRP_1', 'RSRP_2')