Question 3 (Multiple Choice, Worth 2 Points)

Solve [tex]$e^{2x} = 40$[/tex]. Round to the thousandths place.

A. [tex][tex]$x = 0.801$[/tex][/tex]
B. [tex]$x = 3.689$[/tex]
C. [tex]$x = 1.602$[/tex]
D. [tex][tex]$x = 1.844$[/tex][/tex]



Answer :

To solve the equation [tex]\( e^{2x} = 40 \)[/tex] and find the value of [tex]\( x \)[/tex], we can follow these steps:

1. Take the natural logarithm of both sides of the equation:
The natural logarithm (denoted as [tex]\(\ln\)[/tex]) is used because it is the inverse function of the exponential function with base [tex]\(e\)[/tex].
So, applying [tex]\(\ln\)[/tex] to both sides gives us:
[tex]\[ \ln(e^{2x}) = \ln(40) \][/tex]

2. Simplify the left side using logarithm properties:
Recall that [tex]\(\ln(e^{y}) = y\)[/tex]. Applying this property:
[tex]\[ \ln(e^{2x}) = 2x \][/tex]
Therefore, the equation simplifies to:
[tex]\[ 2x = \ln(40) \][/tex]

3. Solve for [tex]\( x \)[/tex]:
To isolate [tex]\( x \)[/tex], divide both sides of the equation by 2:
[tex]\[ x = \frac{\ln(40)}{2} \][/tex]

4. Calculate the value:
[tex]\(\ln(40)\)[/tex] is a constant value that can be approximated using a calculator. Substituting the natural logarithm of 40 in the equation and dividing by 2 results in:
[tex]\[ x \approx 1.844 \][/tex]

So, after rounding to the thousandths place, the value of [tex]\( x \)[/tex] is approximately [tex]\( 1.844 \)[/tex].

Comparing this value to the multiple-choice options provided, we see that:

- [tex]\( x = 0.801 \)[/tex]
- [tex]\( x = 3.689 \)[/tex]
- [tex]\( x = 1.602 \)[/tex]
- [tex]\( x = 1.844 \)[/tex]

The correct answer is [tex]\( \boxed{1.844} \)[/tex].