# Math Help - Mean Value Theorem

1. ## Mean Value Theorem

Using the Mean Value Theorem, prove that ln(103) - ln(100) is less than or equal to 0.03

I tried taking f(x) = 1/x on the interval [100,103]. The average value would then be (1/3)[ln(103)-ln(100)].

I don't know how to proceed after this or even if I'm on the right track.

2. Well, you actually gotta take $f(x)=\ln x$ then exists $c\in(100,103)$ so that $\frac{\ln 103-\ln 100}{3}=\frac{1}{c}.$

On the other hand is $100 so $\frac1{103}<\frac1c<\frac1{100}$ and then $\frac{1}{103}<\frac{\ln 103-\ln 100}{3}<\frac{1}{100},$ so pick the second inequality and $\ln 103-\ln 100<\frac{3}{100}=0,03.$