# Exponential Question

• Mar 27th 2010, 10:30 PM
dag
Exponential Question
I am not positive this is the correct spot for this question ( it is an Algebra question but it was not given in the context of an Algebra class. I am currently working my way through Michael Spivak's book "Calculus"). Here is the question:

$

x + 3^x<4
$

Now just by looking at it, I can see that the answer has to be x<1 but I don't see how I could show that mathematically. Any insights would be appreciated.

Dag
• Mar 28th 2010, 05:56 AM
running-gag
Hi

$f(x) = x + 3^x$ is an increasing function and f(1)=4 therefore for all x<1 f(x)<4