i < s u p > 2 < / s u p >< b r / >< m a t h > ( x + y ) 2 = x 2 + y 2 + 2 x y < m a t h > i {\displaystyle i<sup>2</sup><br/><math>(x+y)^{2}=x^{2}+y^{2}+2xy<math>{\sqrt {i}}}
1 d 2 {\displaystyle {\frac {1}{d^{2}}}} <math> \frac{d^2y}{d^2x}+ω^2
<math>
\frac{d^2y}{d^2x}+ω^2
