hey when Fe react with Cl₂ in water then FeCl₂ is formed. Why not FeCl₃ ?????????

Can anyone please give me link for IL Finar

CAN ANYONE GIVE ME THE LINK FOR DOWNLOADING ORGANIC CHEMISTRY VOL. I & II BY I L FINAR

A tightly wound solenoid of radius 'a' and length 'l' has 'n' turns per unit length.It carries an electric current 'i'.Consider a length 'dx' of the solenoid at a distance 'x' from one end.This contains 'ndx' turns and may be approximated as a circular current 'indx'

(a)Write the magnetic field at the centre of the solenoid due to this circular current.Integrate this expression under proper limits to find the magnetic field at the centre of the solenoid.

(b)Verify that if l>>a,the field tends to B=u₀ni and if a>>l,the field tends to B=u₀ni/2a.

ANS:-(a)u₀ni/[1+(2a/l)²]^1/2 

HURRY UP............

 Find the range of f(x)

  f(x)= sinx/(1+tan²x)^1/2 - cosx/(1+cot²x)^1/2