What is the meaning of two imaginary units in Bicomplex number?

48 Views Asked by At

We know the number of the form w=a+bi+cj+dij; (where a,b,c,d are reals and i,j are independent imaginary units such that i^2=-1=j^2) is called bicomplex number. My question is: How it is possible the units i and j are independent(or different) but i^2=-1=j^2 ?