How can I find the inverse of this function f(x) = sqrt(x) - 7 for x >= 0? my sol is f^-1(x) = (x+7)^2, x>=7

0 ⤊

How can I find the inverse of this function f(x) = sqrt(x) - 7 for x >= 0? my sol is f^-1(x) = (x+7)^2, x>=7

Am I close?

2007-02-24 10:39:30 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics

4 answers

f(x) = sqrt(x) - 7

x = sqrt(f(x)) - 7
x + 7 = sqrt(f(x))
f(x) = (x + 7)^2

f(x >= 0) = ((x >= 0) + 7)^2
f(x >= 0) = ((0,1,2,3,4...) + 7)^2
f(x >= 0) = 49, 64, 81, 100, 121...

ANS : f^-1(x >= 0) >= 49

2007-02-24 12:49:19 · answer #1 · answered by Sherman81 6 · 0⤊ 0⤋

y = sqrt(x) -7 x>=0 y+7=sqrtx so x=(y+7)^2 y+7>=0 y>=-7

Interchange x and y y= (x+7)^2 x>= -7

2007-02-24 19:24:47 · answer #2 · answered by santmann2002 7 · 0⤊ 0⤋

Close. x â¥ -7. f(0) = -7, so f-inv(-7) = 0 requires min x to be -7.

2007-02-24 18:50:08 · answer #3 · answered by Philo 7 · 0⤊ 0⤋

You are but why have solutions only for x>=7?

2007-02-24 18:48:05 · answer #4 · answered by Rob M 4 · 0⤊ 0⤋