The gradient is a vector composed of partial derivatives and is a vector that gives the direction of the steepest ascent.
In a YouTube video that I was watching, it talked about how the gradient descent of the function $f(x,y)$ is $-\nabla f(x,y)$. It does not seem that very intuitive to me that the negative the gradient, or the direction of the steepest ascent, results in the direction of the steepest descent.
I can think of counter-examples to this statement, but I am unsure if I am understanding this part of the video correctly.
This is because $\nabla(-f)=-\nabla f$ is the direction of steepest ascent of the function $-f$, which is therefore the direction of steepest descent of $f$.