Find the extrema and/or the saddle points of the functions a) f(x, y) = ex cos y b) f(x, y) = x² + y² + c) f(x, y) = x sin y 1 x²y²

Note: As per the honor code, the first question can be answered since the exact one wasn’t specified. Please submit a new question by specifying the one you’d like answered in the remaining questions.

Given: $f\left(x,y\right)=e^x\cos y$

To find: Extrema and/or saddle points of the given function.