# Hi, I want to know knee point of a curve including the process of by 2nd derivative. Can anyone help by creating the script.

3 views (last 30 days)
DIPESH THAWANI on 16 Oct 2021
Edited: Star Strider on 16 Oct 2021
I want to calculate knee point of a curve in existing software through 2nd derivative. Can anyone help to create script.

Star Strider on 16 Oct 2021
Edited: Star Strider on 16 Oct 2021
Use the gradient function to calculate the numerical derivative —
x = linspace(0, 10);
y = exp(-0.1*x) .* sin(x);
figure
plot(x, y, x, D1, x, D2)
grid
legend('$y(x)$', '$\frac{dy}{dx}$', '$\frac{d^2y}{dx^2}$', 'Location','best', 'Interpreter','latex')
EDIT — (16 Oct 2021 at 21:22)
I am not certain what the curve is. Additional options (includeing the derivative approach) could be findchangepts or ischange.
.

### Community Treasure Hunt

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

Start Hunting!

Translated by