Exponential Function Plotting From Reverse

Hello,

I want to plot the graph of exponential function but in reverse order. For example I want this plot to start from 5 and decrease until 0 not from 0 to 5. I will also use drawnow to animate the plot. How can I do that time operation? My code is like that. I want this operation comes reversely.

clear all
close all

t = 0:1:150;
x = log(1004*t);
figure

for i=1:numel(t)
    plot(t(i),x(i),'.','Color','r')
    hold on
    drawnow
    ylim([0 30])
    xlim([0 150])
    grid minor
end

Answer 1

[Star Strider]

I initially could not get the 'XDir' to 'reverse' before the loop. Apparently it is necessary to plot something and then set the axes to 'reverse'.

Try this —

t = 150:-1:0;
x = log(1004*t);
figure
Ax = axes;
plot(Ax,NaN,NaN)
Ax.XDir = 'reverse';
hold on
for i=1:numel(t)
    plot(Ax,t(i),x(i),'.','Color','r')
    drawnow
    ylim([0 30])
    xlim([0 150])
    grid minor
end

The animation will not show here, so run it offlline to see the effect.

.

[tinkyminky93]

The only thing that we should do is setting t= 150:-0.1:0

I solved the problem. When I run your code, it is the same as KSSV's graph.

I don't need to reverse the axes. I just need to reverse the time. :)

[Star Strider]

‘I don't need to reverse the axes. I just need to reverse the time. :)’

That was not obvious from the way the question was stated. (I initially reversed ‘t’, however it took a bit of experimentation to also reverse the x-direction. I wanted to provide a complete solution.)

Answer 2

[KSSV]

clear all
close all

t = 0:1:150;
x = log(1004*t);
figure
plot(t,x,'Color','r')
grid minor
set(gca,'XDir','reverse')

[tinkyminky93]

thank you sir, but it does not look like a normal graph, how can we take the point "150" to the right and point "0" to the left?

[tinkyminky93]

I don't know if you have understand my question but it should be like t = 150: -0.1: 0 hope that helps :)

[KSSV]

t = 0:1:150;
x = log(1004*t);
figure
plot(t,x,'Color','r')
grid minor

[tinkyminky93]

Okey sir, that is not what I want to explain but thanks for your effort.