De Moivre's Theorem is a formula that is used to calculate the power of complex numbers. The formula of the theorem states that any real number x and any integer n that (cosx + isinx) to the nth power would equal cos (nx) + isin(nx).
De Moivre's Theorem is important due to its ability to connect complex numbers and trigonometry. Through expanding the left hand side and then comparing both the real and imaginary parts while assuming that x is real, it is possible to get an expression for cos(nx) and sin(nx).
Although it is a theorem, De Moivre's formula can be proven mathematically through induction for natural numbers and extended to all integers from that induction. There is a single limitation in the theorem  it does not work for noninteger powers.
When an equation has a complex number that is taken to a noninteger power, De Moivre's theorem cannot be used due to the fact that the solution can have many different values. Despite this shortcoming, it is generally accepted that the righthand side of an expression that meets these standard can still be a possible value of the power.
De Moivre's theorem and the formula that accompanies it is an integral part of trigonometry.
De Moivre's theorem states that (r cis q) n. = r. n. cis nq, where cis x = cos x + i sin x.
http://wiki.answers.com/Q/What_is_De_Moivre's_theo...

The formula is important because it connects complex numbers.
http://www.chacha.com/question/whatisdemoivre's...

http://mathforum.org/library/drmath/sets…. See this site for lots about the theorem.
http://answers.yahoo.com/question/index?qid=201207...

> Since we know the exact momentum of a photon. This is the flaw. We DON'T know a photon's exact momentum. Note the formula, where its momentum is based on its wavelength. Lambda
http://en.allexperts.com/q/Physics1358/2009/8/unc...
