Question

Find the derivative of f(x) = 2/x at x = -2

Answer 1

Would it just be x=-1?

Answer 2

f(x) = 2*x^(-1)

now use
y=x^n
y'=nx^(n-1)

Answer 3

so -2x^-2?

Answer 4

yes, now plug x =-2.

Answer 5

which is -2/x^2 so -1/2?

Answer 6

correct

Answer 7

right

Answer 8

Wooo thanks.

Answer 9

I got another one like it just ant you to check it. do you want me to start a new question or does doing it on here work?

Answer 10

you can do it here

Answer 11

-9/x at x=-4 so it would be 9x^-2 so 9/x^2 so 9/16?

Answer 12

yes

Answer 13

sorry one last questions. for this one

Answer 14

Find the derivative of f(x) = 7x + 9 at x = 6
When i work it out i get 7x^0 or just 7+9 which is 16 but that isn't an answer choice?

Answer 15

derivative of a constant is zero

Answer 16

What do you mean "of a constant?

Answer 17

9

Answer 18

no x in there hence it is constant with respect to x (the variable which you take the derivative with respect to)

Answer 19

okay so whenever there is no x it automatically becomes a 0?

Answer 20

making it 7+0 therefore 7?

Answer 21

yes (if you take the derivative with respect to x)

Answer 22

see, derivative with respect to x tells you how the function changes when you change x
so if there is no x - no change

Answer 23

Alright :D thanks a lot man :D i think i'm good for now but if i have any more questions i'll let you know if you dont mind that is :P

Answer 24

yw:)