+√x2−4 ∵f(x) will be undefined if 4x2+1=0 or x2−4<0 ∵4x2+1≠0 for x∈R{x2 is always positive } Now, let x2−4<0 ⇒x2<4 ⇒x∈(−2,2) ⇒ Function will be undefined when x∈(−2,2) ∴ Domain of f(x)=R−(−2,2) ∴ Domain of f(x)=R−(−2,2)=(−∞,−2]∪[2,∞)