Cis (matemàtiques)
notació matemàtica per a cos(x) + i sin(x) / From Wikipedia, the free encyclopedia
cis is a mathematical notation defined by cis x = cos x + i sin x, where cos is the cosine function, i is the imaginary unit and sin is the sine function. x is the argument of the complex number (angle between line to point and x-axis in polar form). The notation is less commonly used in mathematics than Euler's formula, eix, which offers an even shorter notation for cos x + i sin x, but cis(x)
is widely used as a name for this function in software libraries.[1]