Big Ideas Math Algebra 2, 2014
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Big Ideas Math Algebra 2, 2014 View details
6. Solving Exponential and Logarithmic Equations
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Exercise 59 Page 339

Use the calculator to graph two different functions, one for each side of the equation.

x ≈ 1.78

Practice makes perfect

To solve the equation by graphing, we first have to create two functions. Each side of the given equation will become its own equation. ln 2x = 3^(- x+2) ⇒ ly=ln 2x y=3^(- x+2) Now we want to draw these graphs using a calculator. We can do this by pressing the Y= button and typing the equations in the two first rows.

Fönster med funktioner

Before we graph these functions, notice that the exponent of 3 is - x+2, so the function will be translated horizontally and we will not be able to see it in the standard viewing window. In order to accommodate this issue, we should change the viewing window. Let's restrict the x-axis. -1 < x < 3 Also, we can change the scale of the y-axis to increase by 5. We can do this by pushing WINDOW.

Fönster med funktioner
Fönster med funktioner

There is one point of intersection of these curves. To find this point we can use the intersect option, which we get by pushing 2nd and TRACE. Now, we select both graphs and provide the calculator with a guess as to where the intersection might be.

Fönster med funktioner
Fönster med funktioner

The solution to the equation is x ≈ 1.78.