Question

MV Calculus: 2B-9B
http://ocw.mit.edu/courses/mathematics/18-02sc-multivariable-calculus-fall-2010/2.-partial-derivatives/part-a-functions-of-two-variables-tangent-approximation-and-optimization/problem-set-4/MIT18_02SC_SupProb2.pdf

Answer at:
http://ocw.mit.edu/courses/mathematics/18-02sc-multivariable-calculus-fall-2010/2.-partial-derivatives/part-a-functions-of-two-variables-tangent-approximation-and-optimization/problem-set-4/MIT18_02SC_SupProbSol2.pdf

Question in reply

Answer 1

\[\Delta w \approx 2 \Delta x + \Delta y\]
How was this derived / found?

Answer 2

They just found the partial derivative of x and y, and then substituted the given value in each case. From part a) of the question the x partial derivative (with substituted value) was 2, the y was 1.

Answer 3

Thanks, that helped!