I had to code how to draw the normal of a curve at a specific point; $t_0 = \frac{2\pi}{5}$ (https://stackoverflow.com/questions/55723461/how-to-plot-the-normal-at-a-point-for-a-given-parametric-curve)
The curve is given by the parametric equations:
$$x(t) = sin(3t)$$
$$y(t) = sin(4t)$$
Where $t[0, 2\pi]$. For this type of parametric curve, the parameter equations for the normal line are given by the following equations:
$$x_{tg} = f(t_0) + f'(t_0)(t-t_0)$$ $$y_{tg} = g(t_0) + f'(t_0)(t-t_0)$$
The problem is that I do not understand why I get the following diagonal:
Could you please explain it with details?
Thanks