Big Ideas Math Integrated I, 2016
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Big Ideas Math Integrated I, 2016 View details
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Exercise 1 Page 325

Use the general form of an exponential function, y=ab^x. Recall that b=1+r, where r is the rate of growth or decay.

Function: y=42 500 (1.03)^x
Graph:

Practice makes perfect
To write an exponential function to model the given situation, let's first recall the general form of an exponential equation. y=a b^x In this formula, a is the initial value and b=1+r, where r is the rate of change. If the function represents growth then r>0, and if it represents decay then r<0.

Writing the Equation

To write the equation, we first need to define the variables. Let y be the annual salary, and let x be the number of years after the initial value. In this case, the initial value is an annual salary of $ 42 500. Since the salary increases by 3 % each year, we have that r=0.03. y=42 500 (1+ 0.03)^x ⇕ y=42 500 ( 1.03)^x To graph the function we will make a table of values. Since time is always greater than or equal to 0, we will assign non-negative values for x.

x 42500(1.03)^x y=42500(1.03)^x
42500(1.03)^() 42500
1 42500(1.03)^1 43775
3 42500(1.03)^3 ≈ 46440
5 42500(1.03)^5 ≈ 49269
9 42500(1.03)^9 ≈ 55452

Let's now plot and connect the obtained points. Since both variables are non-negative, we will only draw in the first quadrant.