Replace y with f−1(x) f – 1 ( x ) to show the final answer. Verify if f−1(x)=x2+5 f – 1 ( x ) = x 2 + 5 is the inverse of f(x)=2x−10 f ( x ) = 2 x – 10.
Contents
 1 Which function is the inverse of f x )= 2x +3?
 2 What is the inverse of function f x )= 9x 7?
 3 What is the inverse of the function f x )= 5 2x?
 4 What is the inverse of the function f x 4x?
 5 Is the inverse of f x always a function?
 6 What is the inverse of the function f x 7x?
 7 What is the inverse of fx 3x 8?
 8 Which function below is the inverse of f x x2 − 25?
 9 What is the inverse of 2 to 9?
 10 What is the inverse of negative 9?
 11 What is the inverse of 2 by 8?
What is the inverse of x2 − 9?
The function f(x)=x2−9 does not have an inverse unless you first restrict its domain to make sure that there is only one xvalue for each yvalue in its range. One such restriction would be [0,∞), in which case the inverse function is g(x)=√x+9. Welcome to MathSE.
What is the inverse function of f x )= 2x 1?
Thus, the Inverse of the function f(x) = 2x + 1 is f – 1 (x) = x/2 – 1/2.
What is the inverse of a function FX?
Inverse Functions Example –
 Example 1:
 Find the inverse of the function f(x) = ln(x – 2)
 Solution:
 First, replace f(x) with y
 So, y = ln(x – 2)
 Replace the equation in exponential way, x – 2 = e y
 Now, solving for x,
 x = 2 + e y
 Now, replace x with y and thus, f 1 (x) = y = 2 + e y
 Example 2:
 Solve: f(x) = 2x + 3, at x = 4
 Solution:
 We have,
 f(4) = 2 × 4 + 3
 f(4) = 11
 Now, let’s apply for reverse on 11.
 f 1 (11) = (11 – 3) / 2
 f 1 (11) = 4
 Magically we get 4 again.
 Therefore, f 1 (f(4)) = 4
So, when we apply function f and its reverse f 1 gives the original value back again, i.e, f 1 (f(x)) = x.
 Example 3:
 Find the inverse for the function f(x) = (3x+2)/(x1)
 Solution:
 First, replace f(x) with y and the function becomes,
 y = (3x+2)/(x1)
 By replacing x with y we get,
 x = (3y+2)/(y1)
 Now, solve y in terms of x :
 x (y – 1) = 3y + 2
 => xy – x = 3y +2
 => xy – 3y = 2 + x
 => y (x – 3) = 2 + x
 => y = (2 + x) / (x – 3)
 So, y = f 1 (x) = (x+2)/(x3)
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An inverse function is a function that returns the original value for which a function has given the output. If f(x) is a function which gives output y, then the inverse function of y, i.e. f 1 (y) will return the value x. Suppose, f(x) = 2x + 3 is a function.
 Let f(x) = 2x+3 = y y = 2x+3 x = (y3)/2 = f 1 (y) This is the inverse of f(x).
 One should not get confused inverse function with reciprocal of function.
 The inverse of the function returns the original value, which was used to produce the output and is denoted by f 1 (x).
 Whereas reciprocal of function is given by 1/f(x) or f(x) 1 For example, f(x) = 2x = y f 1 (y) = y/2 = x, is the inverse of f(x).
But, 1/f(x) = 1/2x = f(x) 1 is the reciprocal of function f(x). Let f(x) = 1/x = y Then inverse of f(x) will be f 1 (y). f 1 (y) = 1/x If we have to find the inverse of trigonometry function sin x = ½, then the value of x is equal to the angle, the sine function of which angle is ½.
What is the inverse of FX = 4x 12?
Solution: An inverse function reverses the operation done by a particular function. In other words, the inverse function undoes the action of the other function. Given, f(x) = 4x – 12 First replace f(x) with y. y = 4x – 12 Next replace x with y and y with x.
Which function is the inverse of f x )= 2x +3?
Solution: We will use the concept of transposition to find the inverse function. We have been given a function f(x) = 2x + 3 For finding inverse we will solve y = 2x + 3 to write x as a function of y and that will be our inverse function. Therefore, we have y = 2x + 3 y – 3 = 2x (y – 3) / 2 = x Now substituting x in place of y and f 1 (x) in place of x, we get, f 1 (x) = (x – 3) / 2 You can use the inverse function formula to verify the result.
What is the inverse of f x )= 2x +8?
Replace y with f−1(x) f – 1 ( x ) to show the final answer. Verify if f−1(x)=x2−4 f – 1 ( x ) = x 2 – 4 is the inverse of f(x)=2x+8 f ( x ) = 2 x + 8.
What is the inverse of f x 2x 7?
Inverse Functions  Math ∞ Blog At the most basic definition, inverse functions are simply the opposite of another function. Instead of f(x) for the function, an inverse function is f^1(y). Inverse functions are not available for every function, but when they are available, it is possible to reverse the original function to determine what the inverse function is.
Reversing a Function Creating an inverse is done by simply reversing the original function. This can be done both ways, so even after an inverse is created, it’s possible to go back to the original function as well. If the original function is f(x)=2x7, the order for the function is to multiply the x by 2 and then subtract 7.
The inverse reverses this, so it adds 7 to the y and then divides by 2. So, the inverse of f(x)=2X7 is f^1(y)=(y+7)/2. Checking to See if the Inverse is Correct It’s important to make sure the inverse that is created is correct. This is done by filling in a number for x and solving the original function.
 Then, use the answer for that as y in the inverse to see if the original number is the answer.
 For instance, use the function f(x)=3x+5.
 First, determine the inverse of the function.
 This would be f^1(y)=(y5)/3 because the inverse function is the reverse of the function.
 Then, solve for x=3.
 The original function would then be f(3)=14.
To see if the inverse is correct, solve it using y=14. So, f^1(14)=(145)/3. This does solve as f^1(14)=3. Since the number from the inverse function matches the number used to solve the function, the inverse was done correctly and the inverse is valid.
F(x)=2x+5Y=2x+5y5=2x(y5)/2=xF^1(x)=(y5)/2
Once the inverse is found, it’s possible to use the steps above to ensure the inverse is correct and valid. There are times when this does not work properly and an inverse cannot be found. Some expressions simply do not have an inverse. Inverse functions are simply reversed functions and it can be easy to determine what the inverse is of a function as long as it has an inverse.
 It’s important to be careful when using either method to find the inverse as the opposite symbol will need to be used for the inverse.
 If the original function had addition, it would become subtraction in the inverse.
 If there was originally division in the function, it would become multiplication in the inverse and so on.
As long as the inverse is valid, using the above method for solving the function and the inverse will enable the student to check to ensure the work was done properly. Functions and inverse functions are useful outside of math class as well. Perhaps a student knows how to convert Celsius to Fahrenheit and they’re given a temperature in Fahrenheit they need know in Celsius.
What is the inverse of function f x )= 9x 7?
Replace y with f−1(x) f – 1 ( x ) to show the final answer. Verify if f−1(x)=x9+79 f – 1 ( x ) = x 9 + 7 9 is the inverse of f(x)=9x−7 f ( x ) = 9 x – 7.
What is the inverse of 1?
Therefore the multiplicative inverse of 1 is 11=1.
What is the inverse function of fx 2x 5?
It becomes x= 2y5.
What is the inverse of the function f x )= 5 2x?
What is the inverse function of f(x) = 5 – 2x? x=5/2y/2 is the inverse function.
What is the inverse of the function f x 4x?
Which represents the inverse of the function f(x) = 4x? h(x) = x + 4, h(x) = x – 4, h(x) = 3/4 x, h(x) = 1/4 x – Summary: The equation which represents the inverse of the function f(x) = 4x is h(x) = 1/4 x.
Is the inverse of f x always a function?
Inverse of Functions MathBitsNotebook(A2 – CCSS Math) Inverse functions were examined in Algebra 1. See the to revisit those skills. A function and its inverse function can be described as the “DO” and the “UNDO” functions, A function takes a starting value, performs some operation on this value, and creates an output answer.
A function composed with its inverse function yields the original starting value. Think of them as “undoing” one another and leaving you right where you started. If functions f and g are inverse functions,, 
Basically speaking, the process of finding an inverse is simply the swapping of the x and y coordinates. This newly formed inverse will be a relation, but may not necessarily be a function.
The inverse of a function may not always be a function ! The original function must be a onetoone function to guarantee that its inverse will also be a function. 
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A function is a onetoone function if and only if each second element corresponds to one and only one first element. (Each x and y value is used only once.)table>
Use the horizontal line test to determine if a function is a onetoone function, If ANY horizontal line intersects your original function in ONLY ONE location, your function will be a onetoone function and its inverse will also be a function, The function y = 2 x + 1, shown at the right, IS a onetoone function and its inverse will also be a function, (Remember that the vertical line test is used to show that a relation is a function.)table>
An inverse relation is the set of ordered pairs obtained by interchanging the first and second elements of each pair in the original function.  
If the graph of a function contains a point ( a, b ), then the graph of the inverse relation of this function contains the point ( b, a ). Should the inverse relation of a function f ( x ) also be a function, this inverse function is denoted by f 1 ( x ). Note: If the original function is a onetoone function, the inverse will be a function, 
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If a function is composed with its inverse function, the result is the starting value. Think of it as the function and the inverse undoing one another when composed. Consider the simple function f ( x ) = and its inverse f 1 ( x ) = More specifically: The answer is the starting value of 2.Finding inverses: Let’s refresh the 3 methods of finding an inverse.
Swap ordered pairs: If your function is defined as a list of ordered pairs, simply swap the x and y values. Remember, the inverse relation will be a function only if the original function is onetoone. 
Example 1: Given function f, find the inverse relation. Is the inverse relation also a function ? Answer: Function f is a onetoone function since the x and y values are used only once. Since function f is a onetoone function, the inverse relation is also a function. Therefore, the inverse function is: Example 2: Determine the inverse of this function. Is the inverse also a function ?
x  1  2  1  2  3  4  3  
f ( x )  2  3  1  1  2  5  1 
Answer: Swap the x and y variables to create the inverse relation. The inverse relation will be the set of ordered pairs: Since function f was not a onetoone function (the y value of 1 was used twice), the inverse relation will NOT be a function (because the x value of 1 now gets mapped to two separate y values which is not possible for functions).
Solve algebraically: Solving for an inverse relation algebraically is a three step process:

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Example 1: Find the inverse of the function Answer:
Remember: Set = y. Swap the variables. Solve for y, You can use the inverse function notation since f ( x ) is a onetoone function. 
Example 2: Find the inverse of the function (given that x is not equal to 0). Answer:
Remember: Set = y. Swap the variables. Eliminate the fraction by multiplying each side by y, Get the y’ s on one side of the equal sign by subtracting y from each side. Isolate the y by factoring out the y,
Solve for y. You can use the inverse function notation since f ( x ) is a onetoone function. 
Example 3: Given f 1 ( x ) = ½ x + 1, express the equation of f ( x ). Answer: At first glance, this question may look like a completely different type of problem, but it is not. Apply the same strategy that was used in Example 1. ( f ( x ) is actually the inverse of f 1 ( x ).)
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Graph: The graph of an inverse relation is the reflection of the original graph over the identity line, y = x, It may be necessary to restrict the domain on certain functions to guarantee that the inverse relation is also a function,Example 1:
Graph the inverse of y = 2 x + 3. Consider the straight line, y = 2 x + 3, as the original function. It is drawn in blue, If reflected over the identity line, y = x, the original function becomes the red dotted graph. The new red graph is also a straight line and passes the vertical line test for functions. The inverse relation of y = 2 x + 3 is also a function. Not all graphs produce an inverse relation which is also a function, 
Example 2:
You can see that the inverse relation exists, but it is NOT a function.  Sketch the graph of the inverse of y = x 2, State whether the inverse is a function. First, we get the inverse by reflecting the given function over the identity line y = x, Then we look at the inverse to see if it is a function (does it pass the vertical line test for functions?), or is it simply a relation. The example at the left shows the original function, y = x 2, in blue, Its reflection over the identity line y = x is shown in red is its inverse relation. The red dashed line will not pass the vertical line test for functions, thus y = x 2 does not have an inverse function – it has an inverse relation. 
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With functions such as y = x 2, it is possible to restrict the domain to obtain an inverse function for a portion of the graph, This means that you will be looking at only a selected section of the original graph that will pass the horizontal line test for the existence of an inverse function. For example:or  by restricting the graph in such a manner, you guarantee the existence of an inverse function for a portion of the graph. (Other restrictions are also possible.) 
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See more about restricting the domain at, bottom of the page.
The graph of will equal x, the starting value. The graph of a function composed with its inverse function is the identity line y = x. 
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For calculator help with inverse of functions 
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Which of the is the inverse of (\ f x 5x 4 \)?
Hence, the inverse of given function is f – 1 ( x ) = – 1 5 ( x + 4 ).
What is the inverse of FX = 3x?
Since f−1(f(x))=x f – 1 ( f ( x ) ) = x and f(f−1(x))=x f ( f – 1 ( x ) ) = x, then f−1(x)=−x3 f – 1 ( x ) = – x 3 is the inverse of f(x)=−3x f ( x ) = – 3 x.
What is the inverse of fx 3x 1?
The inverse of the function f(x)=3x−1 f ( x ) = 3 x − 1 is f−1(x)=x+13 f − 1 ( x ) = x + 1 3.
What is the inverse of the function f x 7x?
Since f−1(f(x))=x f – 1 ( f ( x ) ) = x and f(f−1(x))=x f ( f – 1 ( x ) ) = x, then f−1(x)=x7 f – 1 ( x ) = x 7 is the inverse of f(x)=7x f ( x ) = 7 x.
What is the inverse of fx 3x 8?
Interchanging the x and y variables we get x=3y8. Solving y for x: 3y=x+8 y= x+8/3 Therefore, the inverse of fx=3x8 is f1x= x+8/3 To verify if f and f 1 are inverse functions: f=3 x+8/3 8 f1= 3x8+8/3 =x+8 = 3x/3 =x =x Therefore, f1 is the inverse of f.
Which function below is the inverse of f x x2 − 25?
Which function below is the inverse of f(x) = x 2 – 25? – Summary: The expression ±square root of the quantity x plus 25 function is the inverse of f(x) = x 2 – 25.
What is the inverse of 2 to 9?
The correct option is D 9/2.
What is the inverse of negative 9?
The two addends in an addition equation are interchangeable, which means that the answer to ‘What is the additive inverse of 9?’ or ‘What is the additive inverse of negative 9?’ is 9. Since the additive inverse of 9 is 9, additive inverse is also known as the opposite number.
What is the inverse of 2 by 8?
The additive inverse of 2/8 is 2/8.