evaluate y^ii(2),when y=x^-2
a 0.375
b 0.148
c 0.268
d 0.425

Question

evaluate y^ii(2),when y=x^-2
a 0.375
b 0.148
c 0.268
d 0.425

jamesj · Answer

If y = 1/x^2, what is
y'
and
y''
in general?

That's the first step.

anonymous · Answer

0/0 but i see y^ii (2) how about that?

jamesj · Answer

Still there? 0/0 has nothing to do with it.

The first derivative is
$$ y' = -2.x^{-3} $$
What's the second derivative?

anonymous · Answer

6x

jamesj · Answer

No,
$$ y'' = (-3)(-2)x^{-4} = 6x^{-4} $$
Hence you can now evaluate
$$ y''(2) $$
by substituting $ x = 2 $ into the formula for the second derivative.

anonymous · Answer

wow thanks the answer is near letter d is this correct?

jamesj · Answer

No.  Substitute x=2 into that equation and you have
$$ y''(2) = \frac{6}{16} = \frac{3}{8} $$
Which decimal answer is that equal to?

jamesj · Answer

Are you following?

anonymous · Answer

0.375

anonymous · Answer

sorry i thought what i did is my prof do.he times 6 in the sqrt because for him x=1