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Subsection Comparing Linear Development and you will Rapid Progress

describing the population, $$P\text<,>$$ of a bacteria after t minutes. We say a function has if during each time interval of a fixed length, the population is multiplied by a certain constant amount call the . Consider the table:

We could note that the bacterium population increases by a very important factor out-of $$3$$ each day. Ergo, we point out that $$3$$ is the progress foundation on means. Properties one establish rapid increases is going to be expressed inside a basic mode.

## Analogy 168

The initial value of the population was $$a = 300\text<,>$$ and its weekly growth factor is $$b = 2\text<.>$$ Thus, a formula for the clover dating population after $$t$$ weeks is

## Analogy 170

Exactly how many fresh fruit flies will there be immediately after $$6$$ months? Just after $$3$$ weeks? (Assume that 30 days equals $$4$$ days.)

The initial value of the population was $$a=24\text<,>$$ and its weekly growth factor is $$b=3\text<.>$$ Thus $$P(t) = 24\cdot 3^t$$

## Subsection Linear Progress

The starting value, or the value of $$y$$ at $$x = 0\text<,>$$ is the $$y$$-intercept of the graph, and the rate of change is the slope of the graph. Thus, we can write the equation of a line as

where the constant term, $$b\text<,>$$ is the $$y$$-intercept of the line, and $$m\text<,>$$ the coefficient of $$x\text<,>$$ is the slope of the line. This form for the equation of a line is called the .

## Slope-Intercept Function

$$L$$ is a linear function with initial value $$5$$ and slope $$2\text<;>$$ $$E$$ is an exponential function with initial value $$5$$ and growth factor $$2\text<.>$$ In a way, the growth factor of an exponential function is analogous to the slope of a linear function: Each measures how quickly the function is increasing (or decreasing).

However, for each unit increase in $$t\text<,>$$ $$2$$ units are added to the value of $$L(t)\text<,>$$ whereas the value of $$E(t)$$ is multiplied by $$2\text<.>$$ An exponential function with growth factor $$2$$ eventually grows much more rapidly than a linear function with slope $$2\text<,>$$ as you can see by comparing the graphs in Figure173 or the function values in Tables171 and 172.

## Analogy 174

A solar energy company sold $$$80,000$$ worth of solar collectors last year, its first year of operation. This year its sales rose to$$$88,000\text<,>$$ an increase of $$10$$%. The marketing department must estimate its projected sales for the next $$3$$ years.

In the event your business service predicts you to definitely conversion will grow linearly, exactly what is always to they anticipate the sales full is the coming year? Chart the fresh new estimated sales data across the 2nd $$3$$ many years, so long as conversion increases linearly.

In case your income institution predicts one sales increases significantly, exactly what should they predict product sales overall to be the following year? Chart the projected sales data over the next $$3$$ decades, providing transformation increases significantly.

Let $$L(t)$$ represent the company’s total sales $$t$$ years after starting business, where $$t = 0$$ is the first year of operation. If sales grow linearly, then $$L(t)$$ has the form $$L(t) = mt + b\text<.>$$ Now $$L(0) = 80,000\text<,>$$ so the intercept is $$(0,80000)\text<.>$$ The slope of the graph is

where $$\Delta S = 8000$$ is the increase in sales during the first year. Thus, $$L(t) = 8000t + 80,000\text<,>$$ and sales grow by adding $$$8000$$ each year. The expected sales total for the next year is The values out-of $$L(t)$$ for $$t=0$$ so you can $$t=4$$ receive between line off Table175. The latest linear graph out of $$L(t)$$ is actually revealed when you look at the Figure176. Let $$E(t)$$ represent the company’s sales assuming that sales will grow exponentially. Then $$E(t)$$ has the form $$E(t) = E_0b^t$$ . The percent increase in sales over the first year was $$r = 0.10\text<,>$$ so the growth factor is The initial value, $$E_0\text<,>$$ is $$80,000\text<.>$$ Thus, $$E(t) = 80,000(1.10)^t\text<,>$$ and sales grow by being multiplied each year by $$1.10\text<.>$$ The expected sales total for the next year is The prices off $$E(t)$$ having $$t=0$$ so you’re able to $$t=4$$ are offered during the last column of Table175. New rapid graph away from $$E(t)$$ is actually revealed for the Figure176. ## Analogy 177 A new car begins to depreciate in value as soon as you drive it off the lot. Some models depreciate linearly, and others depreciate exponentially. Suppose you buy a new car for$$$20,000\text<,>$$ and $$1$$ year later its value has decreased to \$$$17,000\text<.>$$

Thus $$b= 0.85$$ so the annual decay factor is $$0.85\text<.>$$ The annual percent depreciation is the percent change from $$\20,000$$ to $$\17,000\text<:>$$

According to the work from the, if the automobile’s well worth reduced linearly then worth of the latest auto just after $$t$$ years try

Shortly after $$5$$ age, the vehicle might be well worth $$\5000$$ beneath the linear design and you will well worth whenever $$\8874$$ beneath the rapid model.

• The domain is perhaps all real quantity and also the variety is all self-confident wide variety.
• In the event the $$b>1$$ then the setting is expanding, when the $$0\lt b\lt step 1$$ then your mode try coming down.
• The $$y$$-intercept is $$(0,a)\text<;>$$ there is no $$x$$-\intercept.

Perhaps not confident of Characteristics out of Exponential Attributes in the list above? Are different new $$a$$ and you will $$b$$ variables regarding pursuing the applet to see additional examples of graphs away from great services, and you can encourage your self that functions listed above hold true. Figure 178 Different variables out of great functions