HORIZONTAL EXPANSIONS AND COMPRESSIONS

How to Do Horizontal Expansions or Compressions in a Function

Let y = f(x) be a function.

In the above function, if we want to do horizontal expansion or compression by a factor of "k", at every where of the function, "x" co-ordinate has to be multiplied by the factor "k". Then, we get the new function 

y  =  f(kx)  

The graph of y = f(kx) can be obtained by expanding or compressing the graph of  y = f(x) horizontally by the factor "k".

It can be done by using the rule given below.

Horizontal Expansion - Example

Question :

Perform the following transformation to the function        y = √x.

               "a horizontal expansion by a factor 0.5"

And also write the formula that gives the requested transformation and draw the graph of both the given function and the transformed function

Answer :

Step 1 :

Since we do horizontal expansion by the factor "0.5", we have to replace  "x" by "0.5x" in the given function y = √x.

Step 2 :

So, the formula that gives the requested transformation is    

y =  √0.5x 

Step 3 :

The graph y =  √0.5x  can be obtained by expanding the graph of the function y = √x horizontally by the factor 0.5. 

(x , y ) -----------------> ( 0.5x , y )

Step 4 :

The graph of the original function (given function)

Step 5 :

The graph of the function in which horizontal expansion made by the factor "0.5".

How to sketch the graph of the function which is  horizontally expanded or compressed ?  

Let "y = f(x)" be the given function and (x , y) by any point on the graph of the function y  =  f(x).

If we want to perform horizontal expansion in the graph of the function  y = f(x) by the factor "0.5", we have to write the point (x , y) as (0.5x ,  y).

That is, "x" co-ordinate of each and every point to be multiplied by the factor 0.5. 

Therefore, any point on the horizontally expanded graph will be in the form of   (0.5x , y)

So, each and every point to be changed according to (0.5x, y) and plot them on the graph.

After having plotted the points, if we connect all the points, we will get the horizontally expanded graph.

The same procedure to be followed for horizontal compression.

Apart from the stuff given in this section,  if you need any other stuff in math, please use our google custom search here.

If you have any feedback about our math content, please mail us : 

v4formath@gmail.com

We always appreciate your feedback. 

You can also visit the following web pages on different stuff in math. 

WORD PROBLEMS

HCF and LCM  word problems

Word problems on simple equations 

Word problems on linear equations 

Word problems on quadratic equations

Algebra word problems

Word problems on trains

Area and perimeter word problems

Word problems on direct variation and inverse variation 

Word problems on unit price

Word problems on unit rate 

Word problems on comparing rates

Converting customary units word problems 

Converting metric units word problems

Word problems on simple interest

Word problems on compound interest

Word problems on types of angles 

Complementary and supplementary angles word problems

Double facts word problems

Trigonometry word problems

Percentage word problems 

Profit and loss word problems 

Markup and markdown word problems 

Decimal word problems

Word problems on fractions

Word problems on mixed fractrions

One step equation word problems

Linear inequalities word problems

Ratio and proportion word problems

Time and work word problems

Word problems on sets and venn diagrams

Word problems on ages

Pythagorean theorem word problems

Percent of a number word problems

Word problems on constant speed

Word problems on average speed 

Word problems on sum of the angles of a triangle is 180 degree

OTHER TOPICS 

Profit and loss shortcuts

Percentage shortcuts

Times table shortcuts

Time, speed and distance shortcuts

Ratio and proportion shortcuts

Domain and range of rational functions

Domain and range of rational functions with holes

Graphing rational functions

Graphing rational functions with holes

Converting repeating decimals in to fractions

Decimal representation of rational numbers

Finding square root using long division

L.C.M method to solve time and work problems

Translating the word problems in to algebraic expressions

Remainder when 2 power 256 is divided by 17

Remainder when 17 power 23 is divided by 16

Sum of all three digit numbers divisible by 6

Sum of all three digit numbers divisible by 7

Sum of all three digit numbers divisible by 8

Sum of all three digit numbers formed using 1, 3, 4

Sum of all three four digit numbers formed with non zero digits

Sum of all three four digit numbers formed using 0, 1, 2, 3

Sum of all three four digit numbers formed using 1, 2, 5, 6