Gilbert Strang, Calculus, 3rd edition (Wellesley-Cambridge Press; MIT OpenCourseWare RES.18-001) §13.4 Directional Derivatives and Gradients, #47 · Multivariable Calculus · Gradient & optimization

(a) Find … and … for the roller-coaster … along the path…

(a) Find $df / d s$ and $df / d t$ for the roller-coaster $f = x y$ along the path $x = cos 2 t, y = sin 2 t$ . (b) Change to $f = x^{2} + y^{2}$ and explain why the slope is zero.

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Gilbert Strang, Calculus, 3rd edition (Wellesley-Cambridge Press; MIT OpenCourseWare RES.18-001) · §13.4 Directional Derivatives and Gradients, #47

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