Modulus of 12 + 16i · MyIBBuddy

Arithmetic sum

\(S_n = \frac{n}{2}\left[2a+(n-1)d\right]\)

Arithmetic term

\(u_n = a + (n-1)d\)

Binomial coefficient

\(\binom{n}{r} = \frac{n!}{r!(n-r)!}\)

Geometric term

\(u_n = ar^{n-1}\)

Modulus

\(|a+bi| = \sqrt{a^2+b^2}\)

Sum to infinity

\(S_\infty = \frac{a}{1-r},\ |r|<1\)