What space Exponential Functions?

Before we get into managing exponential functions and graphing exponential functions, let's first take a look in ~ the general formula and also theory behind exponential functions.

Below is just one of the many general develops of one exponential graph:


A general instance of exponential graph

The exponential role equation to this graph is y=2xy=2^xy=2x, and is the most simple exponential graph we deserve to make. If you're wonder what y=1xy=1^xy=1x would look like, here's the exponential graph:


*
Graph the y = 1^x

Now, as to the reason why the graphs of y=2xy=2^xy=2x and y=1xy=1^xy=1x are so different, the best way to know the theory behind exponential functions is to take a look at some tables.

You are watching: Similarities between linear and exponential functions


*
The table of values of y = 1^x and also y = 2^x

Above you have the right to see 3 tables for three various "base values" – 1, 2 and also 3 – every one of which are to the strength of x. As you can see, because that exponential functions with a "base value" of 1, the value of y stays continuous at 1, since 1 come the power of anything is just 1. The is why the over graph of y=1xy=1^xy=1x is just a right line. In the case of y=2xy=2^xy=2x and y=3xy=3^xy=3x (not pictured), top top the various other hand, we view an increasingly steepening curve for our graph. That is due to the fact that as x increases, the value of y boosts to a bigger and bigger worth each time, or what we contact "exponentially".

Now the we have an idea the what exponential equations look favor in a graph, let's offer the general formula because that exponential functions:

y=abd(x−c)+ky=ab^d(x-c)+ky=abd(x−c)+k

The over formula is a small more facility than previous attributes you've likely operated with, for this reason let's define all of the variables.

y – the worth on the y-axis

a – the upright stretch or compression factor

b – the basic value

x – the value on the x-axis

c – the horizontal translate in factor

d – the horizontal stretch or compression factor

k – the vertical translation factor

In this lesson, we'll only be going end very straightforward exponential functions, so friend don't must worry about some that the above variables. But, so friend have accessibility to every one of the details you need around exponential functions and how come graph exponential functions, let's synopsis what transforming each of this variables does come the graph of one exponential equation.

1) change "a"

Let's to compare the graph that y=2xy=2^xy=2x to an additional exponential equation whereby we change "a", providing us y=(−4)2xy=(-4)2^xy=(−4)2x


A general example of exponential graph
*
compare the graph of y = 2^x and also y = (-4)2^x

By make this transformation, we have actually both "stretched" and also "reflected" the initial graph that y=2xy=2^xy=2x by it's y-values. In order to find "a" through looking at the graph, the most necessary thing to notification is that as soon as x=0 and also we don't have a value for "k", the y-intercept of our graph is constantly going come be equal to "a".

2)Variable "b"

Also recognized as the "base value" this is simply the number that has actually the exponent attached to it. Finding it requires algebra, which will certainly be questioned later in this article.

Variable "c"

Let's compare the graph that y=2xy=2^xy=2x to one more exponential equation whereby we change "c", providing us y=2(x−2)y=2^(x-2)y=2(x−2)


A general instance of exponential graph
*
compare the graph the y = 2^x and also y = x^(x-2)

By making this transformation, we have actually shifted the entire graph to the right two units. If "c" was equal to -2, us would have shifted the whole graph come the left two units.

Variable "d"

Let's compare the graph that y=2xy=2^xy=2x to an additional exponential equation whereby we change "d", providing us y=24xy=2^4xy=24x


A general instance of exponential graph
*
to compare the graph that y = 2^x and also y = 2^(4x)

By making this transformation, we have stretched the initial graph the y=2xy=2^xy=2x through its x-values, similar to just how the variable "a" modifies the role by its y-values. If "d" were an adverse in this example, the exponential function would undergo a horizontal reflection as opposed come the vertical reflection seen with "a".

Variable "k"

Let's to compare the graph the y=2xy=2^xy=2x to an additional exponential equation where we change "k", giving us y=2x+2y=2^x+2y=2x+2


A general instance of exponential graph
*
metric counter table (length)

By make this transformation, we have actually translated the initial graph of y=2xy=2^xy=2x up two units. If "k" were negative in this example, the exponential function would have actually been analyzed down 2 units. "k" is a specifically important variable, as it is likewise equal to what we contact the horizontal asymptote! one asymptote is a value for one of two people x or y that a role approaches, yet never actually equals.

Take for instance the duty y=2xy=2^xy=2x: for this exponential function, k=0, and therefore the "horizontal asymptote" amounts to 0. This renders sense, since no issue what value we put in because that x, we will certainly never obtain y to equal 0. Because that our other function y=2x+2y=2^x+2y=2x+2, k=2, and also therefore the horizontal asymptote amounts to 2. Over there is no worth for x we have the right to use to make y=2.

And that's every one of the variables! Again, numerous of these room more facility than others, therefore it will certainly take time to acquire used to working through them all and becoming comfortable finding them. To get a far better look at exponential functions, and to become familiar v the over general equation, visit this fantastic graphing calculator website here. Take your time to play about with the variables, and also get a much better feel for how an altering each of the variables results the nature of the function.

Now, let's get down to business. Offered an exponential role graph, how deserve to we find the exponential equation?

How To uncover Exponential Functions

Finding the equation the exponential features is frequently a multi-step process, and every difficulty is different based top top the details and form of graph we space given. Given the graph of exponential functions, we require to have the ability to take some details from the graph itself, and also then deal with for the ingredient we are unable to take directly from the graph. Listed below is a perform of every one of the variables us may need to look for, and also how come usually find them:

a – resolve for it utilizing algebra, or it will certainly be given

b – deal with for it making use of algebra, or it will be given

c – permit x = 0 and also imagine "c" is not there, the value of y will certainly equal the y-intercept; currently count how many units the y worth for the y-intercept is from the y-axis, and this will certainly equal "c"

d – deal with for it making use of algebra

k – equal to the worth of the horizontal asymptote

Of course, this are just the basic steps you should take in order to discover the exponential duty equation. The best method to learn just how to carry out this is to shot some practice problems!

Exponential attributes Examples:

Now let's try a pair examples in order to put all of the concept we've covered into practice. Through practice, you'll have the ability to find exponential features with ease!

Example 1:

Determine the exponential role in the type y=abxy=ab^xy=abx that the offered graph.


recognize an exponential duty given its graph

In order to deal with this problem, we're walk to need to find the variables "a" and "b". Together well, we're going to need to solve both of these algebraically, together we can't recognize them indigenous the exponential function graph itself.

Step 1: fix for "a"

To settle for "a", we must pick a point on the graph whereby we can remove bx because we don't yet recognize "b", and therefore we must pick the y-intercept (0,3). Because b0 amounts to 1, we can find that a=3. As a shortcut, since we don't' have actually a worth for k, a is just equal to the y-intercept that this equation.


*
discover a of the equation y = a b^x

Step 2: deal with for "b"

Now that we have actually "a", every we have to do is sub in 3 because that "a", pick one more point, and solve for b. Let's choose the point (1,6). Through all this information, we can uncover that b=2.


Step 3: write the final Equation

Now we that we have found every one of the necessary variables, all that's left is to compose out our final equation in the kind y=abxy=ab^xy=abx. Our last answer is y=(3)2xy=(3)2^xy=(3)2x


Example 2:

Determine the exponential duty in the kind y=a2dx+ky=a2^dx+ky=a2dx+k that the provided graph.


In order to fix this problem, we're walk to require to uncover the variables "a", "d" and also "k". Remember, us can find "k" native the graph, together it is the horizontal asymptote. Because that "a" and also "d", however, we're walk to have to solve because that these algebraically, as we can't recognize them from the exponential duty graph itself.

Step 1: find "k" native the Graph

To discover "k", all we must do is discover the horizontal asymptote, i m sorry is clearly y=6. Therefore, k=6.


Step 2: resolve for "a"

To settle for "a", just like the critical example, we need to pick a point on the graph whereby we can remove 2dx because we don't yet recognize "d", and also therefore we should pick the y-intercept (0,3). Because 20 equals 1, subbing (0, 3) right into y=a2dx+6y=a2^dx+6y=a2dx+6 provides us the a=-3.

See more: How Many Calories In 1 Chocolate Chip Cookie Nutrition Facts


Step 3: settle for "b"

Now the we have "a" and "k", every we have to do is choose another point and fix for b. Let's choose the point (0.25, 0). With all this information, us can discover that d=4.


Step 4: write the final Equation

Now we that we have found every one of the crucial variables, all that's left is to create out our final equation in the type y=abdx+ky=ab^dx+ky=abdx+k. Our final answer is y=(−3)24x+6y=(-3)2^4x+6y=(−3)24x+6


And that's it because that exponential functions! Again, these features are a small more facility than equations because that lines or parabolas, therefore be sure to do numerous practice troubles to gain a hang of the new variables and techniques. With more practice, shortly exponential equations and also the graphs of exponential attributes will it is in no problem at all!