00:01
So in this question, we have a geometric series, and we want to know if it's convergent or divergent.
00:05
Now, it didn't seem to copy well, but i believe what we have here is 10 minus 8 plus 6 .4 minus 5 .12 plus dot, dot, dot.
00:17
Now, why is this geometric? what am i doing to move from one term to the next? well, i'm multiplying by negative four -fifths.
00:29
So 10 times negative four -fifths is negative 8.
00:35
Negative 8 times negative 4 -fifths is positive 6 .4.
00:42
6 .4 times negative 4 -5ths is negative 5 .12, etc.
00:50
And so that's what we call our value of r.
00:53
R is what i multiply by to move from one turn -1.
00:57
To the next.
00:59
So i have an r value this time of negative four -fifths.
01:04
Now, if i want to know if a geometric series converges or diverges, i look at the absolute value of r...