00:02
We're told that 1 over a, 1 over b, 1 over c form an arithmetic sequence.
00:18
Okay, so in particular, for part a, or i guess, in particular, this means that the difference between 1 over c and 1 over b is equal to the common difference.
00:40
And in particular is equal to 1 over b minus 1 over a.
00:50
All right.
00:52
So this is the place where we'll start for a and for part b.
01:04
So for part a, let's go ahead and rewrite the left -hand side and the right -hand side so that we are combining diffractions together.
01:21
So we have b divided by b -c, minus c divided by b c.
01:29
Here we have a divided by ab minus b divided by ab.
01:38
Rewriding that, we have b minus c divided by bc equals a minus b divided by a .b.
01:49
Now, let's go ahead and divide each side by bc and multiply each side by ab...