Question

Assume x and y are functions of t. Evaluate dy/dt for the following: 4x^3-9xy^2+y=-80; dx/dt= 4, x=-3, y=1

Answer 1

y=-82

Answer 2

y+82=0

Answer 3

how did you get that?

Answer 4

It's easy just use combine like terms than you evaluate

Answer 5

ah, my book says we are supposed to first differentiate and then plug in the values

Answer 6

\[4x^3-9xy^2+y=-80\]
\[12x^2x'-9(x'y^2+2xyy')+y'=0\] solve for y'

Answer 7

K, ill do that rly quick

Answer 8

or replace x by -3, y by 1, x' by 4 and then solve for y'

Answer 9

ah that might be easier

Answer 10

thank you!

Answer 11

yes probably easier with the numbers