Question

Let f be the function defined as follows.
y=f(x)=(8x^2)-2x+3

(a) Find the differential of f.
dy=(16x-2)dx
(b) Use your result from part (a) to find the approximate change in y if x changes from 2 to 1.97. (Round your answer to two decimal places.)
dy =

(c) Find the actual change in y if x changes from 2 to 1.97 and compare your result with that obtained in part (b). (Round your answer to two decimal places.)
Δy =

Answer 1

d?= a little bit (change in) ?

dx=0.03
x=1.985
insert into dy=(16x-2)dx to work out dy

Answer 2

Compute y for both values of x, note the change

Answer 3

if i do ((16*1.985)-2)*.03 i get .8928 which isnt right

Answer 4

Is it far off, as for 1.985 you could have chosen instead 1.97 or 2, but with less accuracy?