Let `S=sum_(k=1)^80 1/sqrtk`. Then [S], where [.] denotes the . greatest integer function, equals

Lt_(xto2) [x] where [*] denotes the greatest integer function is equal to

Let f(x)=[|x|] where [.] denotes the greatest integer function, then f'(-1) is

Let f(x)=[|x|] where [.] denotes the greatest integer function, then f'(-1) is

Let S=sum_(r=1)^(117)(1)/(2[sqrt(r)]+1) where [.) denotes the greatest integer function.The value of S is

Let f(x)=(-1)^([x]) where [.] denotes the greatest integer function),then

lim_(xto1) (xsin(x-[x]))/(x-1) , where [.] denotes the greatest integer function, is equal to

lim_(xto1) (xsin(x-[x]))/(x-1) , where [.] denotes the greatest integer function, is equal to