Modular forms are meromorphic functions on the upper half complex
plane which satisfy certain transformation properties. If $t$ is a
modular function of weight $0$ and $F$ is a modular form of weight
$k$ for some subgroup of $SL(2, /mathbb{Z})$, then $F$ as a function
of $t$, satisfies a linear differential equation of $k+1$ order with
algebraic functions of t as coefficients. The differential equations
of this type are closely related to the periods of some families of
elliptic curves and associated surfaces. An important application of
this type of differential equations in number theory is the proof of
irrationality of $/zeta(3)$. This type of differential equations can
also be used to derive some new series expansion for
$/frac{1}{/pi}$.