Core Connections Integrated II, 2015
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Core Connections Integrated II, 2015 View details
1. Section 3.1
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Exercise 64 Page 174

The equation of an exponential function follows the form y=ab^x. The given points must satisfy this equation.

y=7.68(2.5)^x

Practice makes perfect

We want to write an exponential function that passes through the given points. Let's consider the general form for this type of function. y=ab^x The given points must satisfy this equation. Let's substitute (2, 48) and (5, 750) into the formula. y = ab^x ⇒ 48 = ab^2 750 = ab^5 Notice that if we divide the second equation by the first, we will have an equation that we can solve for b.

750/48 = ab^5/ab^2
750/48 = b^5/b^2
â–¼
Solve for b
750/48 = b^(5-2)
750/48 = b^3
15.625 = b^3
sqrt(15.625) = b
2.5 = b
b = 2.5

Now we can start writing our equation. y=a b^x ⇒ y=a( 2.5)^x To find the value of a, let's substitute the point (2, 48), this time into our partial equation.

y = a(2.5)^x
48 = a (2.5)^2
â–¼
Solve for a
48= a(6.25)
48/6.25 = a
7.68 = a
a = 7.68

Finally, we can write the full equation of the exponential function. y= a(2.5)^x ⇒ y= 7.68(2.5)^x