Sunday, November 16, 2008

Electrons and Protons

electron mass = 9.10938188 × 10-31 kilograms

proton mass = 1.67262158 × 10-27 kilograms
elementary charge = 1.60217646 × 10-19 coulombs

Wednesday, September 17, 2008

Limit Definition of e

e = 2.718

lim(1+1/n)n = e
n > inf


NB: lim(1+2/n)n = e2
n > inf

Monday, September 15, 2008

Inverse Trigonometric Derivatives & Integrals

Derivatives
d/dx arcsin(x) = 1 / (1-x2)1/2
d/dx arccos(x) = -1 / (1-x2)1/2
d/dx arctan(x) = 1 / (1+x2)


Integrals
S dx/(a2-x2)1/2 = arcsin (x/a) + C
S dx/a2+x2 = (1/a) arctan (x/a) + C
S dx/x(x2-1)1/2 = arcsec (x) + C

Wednesday, September 10, 2008

List of Common Integrals

S = integral sign


S dx/(x2+a2)3/2 = 1/a2 * x/(x2+a2)1/2
S x*dx/(x2+a2)3/2 = -1/(x2+a2)1/2

Tuesday, September 9, 2008

Kinematic Formulas

vf = vi + at
d = 1/2 (vi + vf)t
d = vit + 1/2 a t2
vf2 = vi2 + 2ad