Question

If  (2,200)
 lies on the line  f(x)=20x
, then what reflection point lies on the line  g(x)=log20x
?(1 point)
(,)

Answers

GPT-4o mini
To find the reflection point of the point (2, 200) across the line represented by the function \( g(x) = \log_{20} x \), we can follow these steps:

1. **Verify the original point on the first line**:
The function \( f(x) = 20x \) at \( x = 2 \) gives:
\[
f(2) = 20 \times 2 = 40
\]
However, point (2, 200) does not lie on \( f(x) \). It appears that the problem might involve finding the reflection given the known point rather than starting with a verification.

2. **Calculate the reflection**:
To find the reflection \( P' \) of point \( P(2, 200) \) across the line \( g(x) = \log_{20}(x) \), we must first determine \( g(2) \):

\[
g(2) = \log_{20}(2) \approx 0.4307 \text{ (using log change of base)}
\]

3. **Find the slope of the line**:
The slope of the line \( y = g(x) \) at \( x = 2 \) can be computed using the derivative:
\[
g'(x) = \frac{1}{x \ln(20)}
\]
So at \( x = 2 \):
\[
g'(2) = \frac{1}{2 \ln(20)}
\]

4. **Equation of the perpendicular line**:
The slope of the line perpendicular to \( g(x) \) at point \( (2, g(2)) \) is the negative reciprocal:
\[
\text{slope}_{\perp} = -\frac{2 \ln(20)}{1}
\]

5. **Finding the intersection**:
Set up the equation of the line through \( (2, 200) \) with slope \( -\frac{2 \ln(20)}{1} \) and find where it intersects with \( g(x) \).

6. **Calculate the reflection**:
Finally, after calculating the intersection point and measuring the distance from \( P \) to this intersection point, you can determine the reflection point \( P' \).

Since the intermediate calculations can get fairly involved, a numerical or graphical method may also be viable for reflecting over a logarithmic function.

### Summary
Due to the complexity of fully defining modifications through typical reflection across non-standard functions, I recommend either determining the intersection using numeric methods or visualizing the reflection graphically should you need further help or specific computational figures. Numerical tools or software (like Python, MATLAB, etc.) would simplify the task of finding intersections and reflections geometrically.

If you need any further clarification or a specific part computed, let me know!