Total number of terms in expansion =n+1
irrational terms = total terms – rational terms
For rational terms; the power of each term should be integer.
Therefore, k must be divisible by 5 and (45-k) by 10.
i.e. the terms having power as multiples of 5.
i.e. 0,5,10,15,20,25,30,35,40 & 45
for k= 5,15,25,35 & 45;
(45-k) do not give an integral power, so these powers have to be rejected.
Now, we have k= 0,10,20,30 & 40 which give us rational terms.
Hence, irrational terms = 46-5 = 41
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