Question

Consider the function $f(x,y,z) = x^4 + 2y^3 + z^2$. The directional derivative of the function at the point $P(-1,1,-1)$ along $(\hat{i} + \hat{j})$, where $\hat{i}$ and $\hat{j}$ are unit vectors in the $x$ and $y$ directions, respectively, rounded off to 2 decimal places, is ___________

Answer 1

The correct Answers is :4.91 or 4.95 Approx