Find the number of terms in the expansion of (4√9+6√8)500 which are integers.
Open in App
Solution
∴ General term Tr+1=500Cr(31/2)500−r(21/2)r=500Cr3250−r/2.2r/2
For r=0,2,4,6,8,10,12,.....500,
Powers of 3 and 2 are integers. Hence, the integers terms =251 Alternative: (91/4+81/6)500 =(31/2+21/2)500 Now, the total number of integral terms will be 1+500L.C.M(2,2) =1+5002 =1+250 =251