How do you find the inverse of y=e^(3x+1)?

1 Answer
Nov 26, 2015

If z_x is the inverse of y_x =e^(3x+1)
then z_x = (ln(x)-1)/3
(with some restrictions)

Explanation:

If z_x is the inverse of y_x
color(white)("XXX")y_(z_x) = x (by definition of inverse)

but
color(white)("XXX")y_(z_x) = e^(3z_x+1) (by definition of y_x)

therefore
color(white)("XXX")e^(3z_x+1) = x

and taking the natural log of both sides
color(white)("XXX")3z_x+1=ln(x)

rArr
color(white)("XXX")z_x= (ln(x)-1)/3

Note however that for certain values of x,
y_x generates non-reversible values (because of limitations on argument values for the ln function)