Formula:-

(i)A function f : X → Y is defined to be invertible, if there exists a function g : Y → X

such that gof =I_x and fog = I_y .The function g is called the inverse of f and is denoted by f^-1

f(x)=y

f^-1(y)=x

f(x)=1

f^-1(1)=x

x⁴=1

x⁴-1=0

(x-1)(x²+1)=0

x=-1,1,i,-i

f^–1(1)={-1,-i,1,i}