Question

Given `log_b 2= 0.3562`, `log_b 3=0.5646`, and `log_b 5=0.8271`, how do you evaluate `log_b15`?

Answer 1

`log_b15=1.3917`

Explanation:

To calculate `log_b15` we use the formula `log_ba*c=log_ba+log_bc`

First we have to write `15` as a product of numbers `2,3 and 5`. Number `2` will not be used because `15` is an odd number, but we can write that `15=3*5`

Now we can use the formula above to write the logarythm as a sum of 2 given values.

`log_b15=log_b3*5=log_b3+log_b5=0.5646+0.8271=1.3917`