00:01
Suppose we have a sequence defined by the following where n starts at 1 and goes to positive infinity, where n equals 1 is the first term, it equals 2 is the second term, and so on and so forth.
00:09
I want to determine what type of monotonic sequence is.
00:13
Recall that monotonic means constantly increasing or constantly decreasing.
00:19
Or could be non -increasing, maybe increasing, but some values are equal or non -decreasing.
00:23
So what i can analyze is the n plus first term all over the nth term, right? and i'm analyzing is this equal to one? if so, the numerator equals the denominator, and it's not growing.
00:33
Is it greater than one, then the numerator is greater than the denominator, so it's growing, or is it less than one than the denominator is greater than the numerator? so the n plus first term, just replace n with n plus 1, 5n plus 1, all divided by 2 to the n plus 1, squared, all over the nth term, 5 to the end, over 2 n squared.
00:57
So what i could do here is simplify this a little bit.
01:03
When i'm adding exponents, multiplying exponents with the same base, right? fib first, n plus 1 squared, right, n plus 1 times n plus 1, when i factored that out, plus 2 n plus 1, and this is 2 n squared times 2 to the 2 n times 2.
01:23
And then since i'm dividing fractions, multiply by the reciprocal, 2 n squared, all over 5n...