Question

Find the equation of the plane tangent to f(x,y)= x^2+2xy^2+x^3y when x=2 and y=3


Calculus 3

Answer 1

Start by partially differentiating your function with respect to x, and then with respect to y.

Answer 2

fx=2x+2y^2+x^3y
fy=4xy+x^3

then what?

Answer 3

Ok so now you put your values of (2,3) into each one of those

Answer 4

fx=58 and fy=32

Answer 5

i got an answer of z-64=58(x-2)+32(y-3) but that does not sound correct.

Answer 6

Ooh, you're one step ahead of me, I'm doing at the same time.

Yeah that's what I get, and I think it's right, well done :)

Answer 7

Just multiply those brackets out to get z = 58x +32y -148

Answer 8

Ok! Thank you very much!

Answer 9

No problem :)