Question

Find the slope of the graph of the function at F(x) =4/x^2 when x=5

Answer 1

f(5)=4/5^2=5/25

Answer 2

Oh, that's all? Thanks so much!

Answer 3

But I need to find f'(5), not just f(5)

Answer 4

F(x) =4/x^2
y =4/x^2

to find the inverse you need to change the x and y then solve for y

x = 4/y^2

y^2*x=4
y^2=4/x
sqrt(y^2)=sqrt(4)/sqrt(x)
y = 2/sqrt(x) = 2sqrt(x)/x

Answer 5

2*sqrt(5)/5

Answer 6

does that look right?

Answer 7

errr, I don't think so, sorry : /

These are my answer choices:
A. -8/5
B. 8/125
C. 8/5
D. -8/125

Answer 8

by f' u mean derivative or inverse

Answer 9

f=4/x^2 = 4x^(-2)
f'=-2*4*x^-3= -8/x^3
f'(5) =-8/5^3=-8/125

Answer 10

Ohhh, that makes so much sense. Thanks!!

Answer 11

For some reason, I can never remember how to rewrite exponents that are in fractions. Or whenever a root is involved.

Answer 12

How would you do 3x^2+5x-6/x^2 when x=-5?

My answer choices end up with a fraction with 3137 as the numerator somehow