A few days ago

# Can anyone give the inverse function of f(x) = x^2 – 3x + 5?

I’m having a problem in finding the inverse of quadratic functions and it’ll be appreciated if those who know share their knowledge. Thanks!

A few days ago
Anonymous

If y = x^2 – 3x + 5,

then x^2 – 3x + (5 – y) = 0

x = ( 3 +/- sqrt(9 – 4(5 – y)) ) / 2

= ( 3 +/- sqrt(4y – 11) ) / 2

The inverse function consists of two parts:

f^(-1)(x) = (3 + sqrt(4x – 11)) / 2

and

f^(-1)(x) = (3 – sqrt(4x – 11)) / 2

That is not strictly a function as it is multi-valued.

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4 years ago
osullivan
A) no answer (not one of the solutions ARE the wonderful option (-2, -5) a million) y=x2+3x+5 y=5x+5 2) (5x+5)=-5 5x= -10 x=-2 So, you plug in x (-2) to locate the fee of y y= (-2)2+3(-2)+5 y=-4-6+5 y= -5 the respond is x= -2, y= -5, aka (-2,-5) decision A.) does no longer be the wonderful option, using fact there’s a answer and you will be able to locate it. the the wonderful option answer might desire to be (-2,-5) or not one of the ABOVE, all solutions are incorrect!
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A few days ago
Anonymous
I’m a bit rusty with this, so sorry if this is completely wrong, but i think you need to complete the square first to solve the problem.

f(x)= (x-(3/2))^2 – (9/4) + 5 = (x-1.5)^2 + (11/4)

then

f(y)= (y- 1.5)^2 + (11/4)

x= (y-1.5)^2 + (11/4)

(y-1.5)^2= x – (11/4)

y- 1.5 = +/-squareroot(x – (11/4))

therefore inverse function/s are:

y = +/-squareroot (x-(11/4)) + 1.5

sorry if that was really hard to follow and/or just plain wrong!

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