Question

I need help. Basically, I need to figure out the dependent and independent value of a function.

Answer 1

Answer:

• x = log(y/4)/log(1.0256)
• your answer for y=12 is correct

Step-by-step explanation:

The question is asking you to solve ...

   y = f(x)

for x. (In other words, find the inverse function.)

You already did this using a constant for y. Do the same thing with y instead of the constant.

  y = 4(1.0256^x)

  y/4 = 1.0256^x . . . . . . . divide by 4

  log(y/4) = x·log(1.0256) . . . . . take logs

  log(y/4)/log(1.0256) = x . . . . . divide by the coefficient of x

Now, you have a model for x in terms of y, which is what the question is asking for.

  x = log(y/4)/log(1.0256) . . . . . . . exact expression

When y=12, this is ...

  x = log(12/4)/log(1.0256) ≈ 43.46 . . . . weeks

_____

This is a linear equation in log(y), so can be written as such:

  x = 91.0912·log(y) -54.8424 . . . . . approximate expression