Question

If f (x) = x^2 + 1 and g (x) =1/x - 1. Find the value of (f of g) (10)

Answer 1

is g(x) = 1 / (x - 1) ??

Answer 2

or (1/x) - 1 ?

Answer 3

(1/x)-1

Answer 4

ok
(f of g = ( 1/x - 1 )^2 + 1
= 1/x^2 - 2/x + 2

f of g (10) = 1/100 - 2/10 + 2 = 1/100 - 20/100 + 200/100 = 181/100
= 1.81

Answer 5

im having a hard time following this..can you use the equation to write it better pls

Answer 6

ill try

Answer 7

\[f of g = (1divx - 1)^2 + 1\]

Answer 8

thats not what i intended

Answer 9

\[f of g = (1/x - 1)^2 + 1\]

Answer 10

\[= 1/x ^{2} - 2/x + 2\]

Answer 11

i dont know how to do more than one line!

Answer 12

i understand now but how do you get the +2

Answer 13

now substitute x = 10 in this exression

right expanding the brackets gives 1/x2−2/x+1
then add 1

Answer 14

i did two steps in one

Answer 15

ok thanks

Answer 16

1/x2−2/x+1 + 1

Answer 17

yw - i'm not very good with the equation thing!

Answer 18

i dont really mind whether someone uses that or not...it was just extremely hard to follow

Answer 19

what is f^-1(x) if f(x) = (5x-3)/(2-x)

how do you find that

Answer 20

ok one way is to let y = (5x-3)/ (2-x)
then find x in terms of y
then replace y by x in this result

this gives f^-1(x) , the inverse of f(x)

Answer 21

you need help with that?

Answer 22

yea

Answer 23

ok first cross-multiply
y(2-x) = 5x-3
2y - xy = 5x-3
5x + xy = 2y+3
x = (2y+3) / ( y+5)
f^-1(x) = (2x+3) / (x+ 5) replacing y's by x's

Answer 24

after fourth line i could have typed
x(y + 5) = 2y+3
then divide both sides by (y+5)

Answer 25

thank you very much. i have to leave now
i hope i can find you later on

Answer 26

yw - sorry - ill be turning in very soon - i'm in uk