limits...

anyone..reply.......

ok let me give u a hint
just write the expansion of LHS

2^-1tan(x/2)+2^-2tan(x/2²)+.......+2^-ntan(x/2^-n) =S

now add cotx on both side, on lhs write

cotx = (1-tan²(x/2))/2tan(x/2)

& go on simplifing, u will get a definite pattern

at last u will get

lim n-> infty 2^-ncot(x/2ⁿ)

which gives limit as 1/x

so the limit S = (1/x) - cotx

:)