The celestial sphere for observers in Seattle and any other observer at the same latitude (47Â° N) on the Earth is shown above. For another more detailed example, let's choose Los Angeles at latitude 34Â° N. The NCP is therefore 34 degrees above the north horizon.
Euler number. For other uses, see List of things named after Leonhard Euler Â§ Euler's numbers. In mathematics, the Euler numbers are a sequence En of integers (sequence A122045 in the OEIS) defined by the Taylor series expansion. where cosh t is the hyperbolic cosine. The Euler numbers appear as a special value of the Euler polynomials.
Euler's formula states that, for any real number x: where e is the base of the natural logarithm, i is the imaginary unit, and cos and sin are the trigonometric functions cosine and sine respectively, with the argument x given in radians. This complex exponential function is sometimes denoted cis(x) (cosine plus i sine). The formula is still valid if x is a complex number, and so some authors refer to the more general complex version as Euler's formula. Euler's formula is ubiquitous in mathematics, physics, and engineering.