Answer
Earlier solution of problems like \[{{x}^{2}}+1=0\] and \[\sqrt{-49}\] were thought to be impossible, then there is a Greek mathematician and engineer Heron of Alexandria is the one to discover the imaginary number to find the solution above mentioned problem.
Application: Imaginary numbers are used to find the solution of the square root of the negative numbers.
Curiosities: curiosities related to imaginary numbers are:
The square root of imaginary number \[i\]has both real and imaginary parts.
