Q.

The number of integral terms in the expansion of (31/2+51/4)680 is equal to ___________ .              [2023]


Ans.

(171)

The expansion of the general term is

=Cr680(31/2)680-r(51/4)r=Cr6803680-r25r4

Possible values of r, where r4 is an integer

         r=0,4,8,12,,680

All these values of r are accepted as well.

Hence, number of integral terms=171