Pedro has created the function f(x) = the quantity of 4x minus 3, divided by 2 to represent the number of assignments he has completed, where x represents the number of weeks in the course. Pedro discovers that using the inverse function to solve for x = 30, he can predict when he will have 30 assignments completed. Explain to Pedro how to accomplish this, using complete sentences.

Respuesta :

Let

x-------> the number of weeks in the course

f(x)------> the number of assignments that Pedro has completed

we know that

[tex] f(x) = (4x-3)/2[/tex]

Step [tex] 1 [/tex]

Find the inverse function of f(x)

[tex] f(x) = (4x-3)/2[/tex]

Let

y=f(x)

[tex] y= (4x-3)/2[/tex]

exchange the variables x for y and  y for x

[tex] x= (4y-3)/2[/tex]

Clear variable y

[tex]x= (4y-3)/2\\ 2x= 4y-3\\ 4y=2x+3\\ y=(2x+3)/4[/tex]

Let

[tex] f(x)^{-1}=y [/tex]

[tex] f(x)^{-1}=(2x+3)/4 [/tex] ------> this is the inverse function

where

x ------> the number of assignments that Pedro has completed

f(x)^{-1}------> the number of weeks in the course

Solve for [tex] x=30[/tex]

substitute

[tex] f(x)^{-1}=(2x+3)/4 [/tex]

[tex] f(x)^{-1}=(2*30+3)/4 [/tex]

[tex] f(x)^{-1}=15.75 [/tex]

therefore

the answer is

[tex] 15\frac{3}{4}\ weeks[/tex]

Answer

Find  when he will have 30 assignments completed for the inverse function.

To prove

As given

Pedro has created the function.

[tex]f(x) = \frac{4x -3}{2}[/tex]

Where  x represents the number of weeks in the course .

Pedro discovers that using the inverse function to solve for x = 30.

he can predict when he will have 30 assignments completed.

Now find the inverse of the function f(x) .

[tex]Take\ y = f(x) = \frac{4x -3}{2}[/tex]

[tex]2y + 3 = 4x [/tex]

[tex]x = \frac{2y + 3}{4}[/tex]

Now change the y variable into x. (Because this is inverse function of f(x)).

Thus

[tex](f(x))^{-1} = \frac{2x + 3}{4}[/tex]

Thus this is the inverse function of f(x).

Put x = 30

[tex](f(x))^{-1} = \frac{2\times 30 + 3}{4}[/tex]

[tex](f(x))^{-1} = \frac{60 + 3}{4}[/tex]

[tex](f(x))^{-1} = \frac{63}{4}[/tex]

[tex]Therefore\ in\ \frac{63}{4}\ weeks\ Pedro\ completed\ 30\ assignment.[/tex]

In mixed fraction form

[tex]Therefore\ in\ 15 \frac{3}{4}\ weeks\ Pedro\ completed\ 30\ assignment.[/tex]



 



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