Question

Calculate the derivative:
dP/dV where v=-2 and p=4/v

no idea how to start this one.

Answer 1

can u calculate d/dv(v^n) ?

Answer 2

\[nx ^{n-1}\]

Answer 3

right :)
\(so\quad d/dv(1/v) = d/dv(v^{-1})=?\)

Answer 4

-v^-2?

Answer 5

that is correct ! :)
so
\(d/dv(4/v)= 4 d/dv(1/v)=?\)

Answer 6

because 4 is a constant and can be taken out from derivative

Answer 7

=4

Answer 8

dP/dv = d/dv(4/v) = 4 d/dv(1/v) = 4 \((-v^{-2})\)
got this ?
now just put v= -2 here

Answer 9

??

Answer 10

that all equals one, right?

Answer 11

4(-v^-2) = 4(2^-2)=4 times 1/4 = 1

Answer 12

\(\huge4(-(-2)^{(-2)})= -4(\frac{1}{(-2)^2})=\frac{-4}{4}=?\)
u just missed a - *minus* sign

Answer 13

shouldn't that be a pus 2?

Answer 14

-v = -(-2) = 2

Answer 15

but the derivative, does not contain -v
derivative is \(\huge -v^{-2}= -\frac{1}{v^2}\)

Answer 16

so the derivative of v=-1

Answer 17

derivative of v will be +1
but why do u need derivative of v ?

Answer 18

the question is the derivative of dP/dV and you told me to get the derivative of v ..
and i said it was plus one then you said i was wrong and that it's -4/4

Answer 19

im just trying to find out the answer haha.

Answer 20

i never said that derivative of v , +1 is wrong....

Answer 21

im confused as to what you are trying to get me to do then.

Answer 22

i just said that u missed a minus sign here
"4(-v^-2) = 4(2^-2)=4 times 1/4 = 1 "
it should be
4(-v^-2) = 4(-(-2)^-2)=4 times (-1/4) = -1
got this ?

Answer 23

sorry, if i confused you....

Answer 24

and is that the derivative for v?

Answer 25

u need to calculate derivative of P, dP/dv which we worked out as -1 and thats the final answer
we don't need derivative of v here(which is 1 bdw)

Answer 26

so my answer is -1?

Answer 27

YES ! :)

Answer 28

thank you so much !!!

Answer 29

thankss

Answer 30

welcome ^_^