How many rational terms are in the given expansion?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
The binomial expansion is ( 3 + 4 5 ) 2 0 0 = k = 0 ∑ 2 0 0 ( k 2 0 0 ) ( 3 ) 2 0 0 − k ( 4 5 ) k . There are 201 terms; however, they are only rational if k is a multiple of 4 and 2 0 0 − k is a multiple of 2. If the former is true, then the latter is also true; thus the rational terms are those with k = 0 , 4 , 8 , … , 2 0 0 .
There are 5 1 of these terms.
They are of the form t 4 n = ( 4 n 2 0 0 ) ⋅ 9 5 0 − n ⋅ 5 n , n = 0 , 1 , 2 , … , 5 0 .