I have a formula:
Weight=onerepmax*(0.488 + 0.538 * ln(-0.075*reps))
And I need to solve for reps given a onerepmax and a weight.
I got as far as:
ln(-0.075*reps) = ((weight/(onerepmax)) - 0.488)/0.538
But I am not sure how I can move the reps out of the log base e function.
In general, $$ \ln(x) = y \iff x = e^y $$ where $e \approx 2.718$ is Euler's constant (on the assumption you are using the base-$e$ logarithm). Hence, raise both sides to the power of $e$ to get $$ -0.075 \cdot \text{reps} = \exp \left( \frac{ \frac{\text{weight}}{\text{one_rep_max}} - 0.488}{0.538} \right) $$ where $$ \exp z := e^z $$ for notational pleasantry.
You can then continuing solving/simplifying from here.
