Even number 2,4,6 so p(even)=3/6=1/2
Odd number 1,3,5 so p(odd)=3/6=1/2
Now applying reasoning ...suppose (a+b) to the power 2
Then number of terms=3
(a+b) to the power 5 then nubmer of terms=6
Here given n=odd say 2k+1 so (p-1/2 for odd+p-1/2 for even)
Whole to the power 2k+1
So total number of terms 2k+2
k+1 terms contains even power of odd and k+1 terms contains odd power of odd ...
So probablity (k+1)/(2k+2)=1/2
PLS CHECK IS IT CORRECT REASONING...
Yes,you can also use this method but I just use the general method
Thank you sir..