सरल शब्दों में आयलर सूत्र सभी बहुफलकों पर परिभाषित है (ie. a 3 dimensional figure that has face,vertex & edge present in them like cube,cuboid etc.) मुख्य सूत्र निम्न है : फलक + शीर्ष = कोर + 2 
या F + V = E + 2
या F + V - E = 2 
YOU CAN EVEN PRACTICALY EXPERMENT THIS FORMULA ON EVERY POLYHEDRON (it would surely exist on each on of them). NOW LET'S MOVE AHEAD & KNOW MORE ABOUT THE EULER'S FORMULA. LETS KNOW ABOUT ITS HISTORY AS MENTIONED BELOW :-
Euler's formula was proven for the first time by Roger Cotes in 1714 in the form

(where "ln" means natural logarithm, i.e. log with base "e").

It was Euler who published the equation in its current form in 1748, basing his proof on the infinite series of both sides being equal. Neither of these men saw the geometrical interpretation of the formula: the view of complex numbers as points in the complex plane arose only some 50 years later (see Caspar Wessel). Euler considered it natural to introduce students to complex numbers much earlier than we do today. In his elementary algebra text book, 
"Elements of Algebra", he introduces these numbers almost at once and then uses them in a natural way throughout.

समिश्र संख्या सिद्धान्त में यूलर के सूत्र का उपयोग
Differential equation definition
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