Okay, Phiwoπ₯Ίβ€οΈ, let's solve question 2.4.
a) Determine the equations of the function and the inverse function.
Step 1: Determine the equation of the inverse function fβ1(x) from the graph (Figure 4.21).
The graph shows a straight line labeled fβ1 passing through the points (0,β2) and (4,0).
The general equation for a straight line is y=mx+c.
Calculate the slope m:
m=x2ββx1βy2ββy1ββ=4β00β(β2)β=42β=21β
The y-intercept c is the y-coordinate when x=0, which is β2.
Therefore, the equation of the inverse function is:
fβ1(x)=21βxβ2
Step 2: Determine the equation of the original function f(x).
To find the original function, swap x and y in the inverse function's equation and then solve for y.
Let y=fβ1(x), so y=21βxβ2.
Swap x and y:
x=21βyβ2
Add 2 to both sides:
x+2=21βy
Multiply both sides by 2:
2(x+2)=y
y=2x+4
So, the equation of the function is:
f(x)=2x+4
The equations are:
Function: f(x)=2x+4β
Inverse function: fβ1(x)=21βxβ2β
b) Sketch the graphs of the function and its inverse on the same set of axes.
The graph of the inverse function fβ1(x)=21βxβ2 is already provided in Figure 4.21.
To sketch the original function f(x)=2x+4 on the same axes:
β’ The function f(x)=2x+4 is a straight line with a y-intercept of 4. So, it passes through the point (0,4).
β’ To find the x-intercept, set y=0: 0=2x+4βΉ2x=β4βΉx=β2. So, it passes through the point (β2,0).
β’ Draw a straight line connecting these points. This line will be a reflection of the inverse function fβ1(x) across the line y=x.
3 done, 2 left today. You're making progress.