What Is the Domain and Range of G(F(x))?

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Homework Help Overview

The discussion revolves around finding the composition of functions G(F(x)), where F(x) = √(2x-1) and G(x) = x/(x-2). Participants are tasked with determining the domain and range of this composition.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the expression for G(F(x)) and raise questions about the validity of the domain restrictions, particularly concerning the values of x that lead to square roots of negative numbers and division by zero.

Discussion Status

There is an ongoing examination of the conditions under which the functions are defined. Some participants are questioning the correctness of the domain values proposed, particularly x ≠ 3/2 and x ≤ 1/2, while others are exploring the implications of these conditions on the range.

Contextual Notes

Participants are navigating through the implications of square root functions and rational expressions, with specific attention to the constraints these impose on the values of x. There is a noted confusion regarding the algebraic manipulations leading to the domain restrictions.

Wa1337
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Homework Statement


If F(x)=√(2x-1) and G(x) = x/(x-2), find G(F(x)) and its domain & range.

Homework Equations


The Attempt at a Solution


G(F(x)) = ((√2x-1)/(√(2x-1)-2)

x ≠ 3/2, x </= 1/2

Where do I go from here?
 
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x \leq \frac{1}{2} is wrong

How did you get x ≠ 3/2?
 
Wa1337 said:

Homework Statement


If F(x)=√(2x-1) and G(x) = x/(x-2), find G(F(x)) and its domain & range.

The Attempt at a Solution


G(F(x)) = ((√2x-1)/(√(2x-1)-2)

x ≠ 3/2, x </= 1/2

Where do I go from here?
If x < 1/2 , then you are taking then you are taking the square root of a negative number.

Perhaps you meant x ≰ 1/2 . If that's the case, it's more straight forward to say, x > 1/2 .

Your answer of x ≠ 3/2 is incorrect.

How about the range ?
 
SammyS said:
If x < 1/2 , then you are taking then you are taking the square root of a negative number.

Perhaps you meant x ≰ 1/2 . If that's the case, it's more straight forward to say, x > 1/2 .

Your answer of x ≠ 3/2 is incorrect.

How about the range ?

Well i thought the denominator could not equal 0, so I did √(2x-1) - 2 ≠ 0 and got x ≠ 3/2.

For the numerator I thought that square roots can't be negative, so they should be >/= 0. So i did √(2x-1) there and got x </= 1/2.

I don't know how to get the range from here, little confused
 
Wa1337 said:
Well i thought the denominator could not equal 0, so I did √(2x-1) - 2 ≠ 0 and got x ≠ 3/2.

For the numerator I thought that square roots can't be negative, so they should be >/= 0. So i did √(2x-1) there and got x </= 1/2.

I don't know how to get the range from here, little confused
√(4) = 2, so 2x - 1 = 4 will give you 2 - 2 which would be division by zero. That solution is not x = 3/2. Check your algebra.

You said "For the numerator I thought that square roots can't be negative, so ... ". That's not quite right. What is true for this case is that you can't take the square root of a negative number. Therefore, you need 2x-1 ≥ 0 . That doesn't give you x ≤ 1/2 .
 

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