Domain, Range & Inverse of a Function

In summary, the method to solve part (iv) & (v) involves converting the given function into general form and then comparing it with the general form of a parabola. The inverse relation is found by swapping the x and y variables, and the domain of the original relation is equivalent to the range of the inverse relation. The specific steps for finding the inverse depend on the given function. In this case, completing the square is used to find the inverse function for two separate intervals, resulting in two one-to-one functions.
  • #1
bllnsr
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Homework Statement


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How to solve part (iv) & (v)

Homework Equations


general form : [itex]y = a(x-h)^2 + k[/itex]

The Attempt at a Solution


In part (iv) for finding domain and range I converted g(x) in general form and then compared it with general form.
 
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  • #2
The inverse relation of y=8x-x2 is x=8y-y2.

Also, the domain of the original relation is the range of the inverse relation in general. Specifics depend...
 
  • #3
I don't believe that is quite what is being asked. Completing the square, 8x- x2= 16- 16+ 8x- x2= 16- (x-4)2. The graph of that is a parabola having vertex at (4, 16). The function f(x)= 16- (x- 4)2 with [itex]x\le 4[/itex] has inverse function [itex]f^-1(x)= 4- \sqrt{x- 16}[/itex] while the function f(x)= 16- (x- 4)2 with [itex]x\ge 4 has inverse function [itex]f^-1(x)= 4+ \sqrt{x- 16}[/itex].

By separating at the vertex, we cut the given function into to one-to-one that now have inverses.
 

Related to Domain, Range & Inverse of a Function

1. What is a domain of a function?

The domain of a function is the set of input values for which the function is defined. It is the set of all possible x-values that can be plugged into the function to produce a valid output.

2. What is a range of a function?

The range of a function is the set of output values that the function can produce for a given set of input values. It is the set of all possible y-values that can be obtained by evaluating the function.

3. How do you find the domain and range of a function?

To find the domain of a function, you need to look for any restrictions on the input values. This can include restrictions on the values of x (such as dividing by 0) and restrictions on the type of numbers allowed (such as negative numbers under a radical). The range can be found by looking at the output values that the function can produce.

4. What is an inverse function?

An inverse function is a function that "undoes" the original function. It switches the input and output values, so that the original output becomes the input and vice versa. For a function to have an inverse, it must pass the horizontal line test, meaning that no two different input values can produce the same output value.

5. How do you find the inverse of a function?

To find the inverse of a function, you can follow these steps:

1. Replace f(x) with y.

2. Switch the x and y variables.

3. Solve for y to get the inverse function.

4. Check that the inverse function passes the horizontal line test.

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