Post a New Question

Calculus

posted by on .

Find a formula for the inverse of the function. f(x) = (1 + 9x) / (8 - 4x)

  • Calculus - ,

    let y = (1+9x)/(8-4x)
    for inverse, interchange the x and y variables

    x = (1+9y)/(8-4y)
    now solve this for y .....

    8x - 4xy = 1 + 9y
    8x - 1 = 9y + 4xy
    y(9+4x) = 8x-1

    y = (8x-1)/(9+4x)
    or
    f^-1 (x) = (8x-1)/(9+4x)

    check with some arbitrary x
    say x = -1
    f(-1) = (1-9)/(8+4) = -8/12 = -2/3
    f^-1 (-2/3)
    = (8(-2/3) - 1)/(9 + 4(-2/3))
    = (-19/3) / (19/3)
    = -1 , as expected
    "more than likely" my answer is correct.

Answer This Question

First Name:
School Subject:
Answer:

Related Questions

More Related Questions

Post a New Question