fix equation

ch01.asciidoc

@@ -42,20 +42,21 @@ image::images/ecc-addition.png["Addition operator on points of an elliptic curve
 Bitcoin specifically uses the +secp256k1+ elliptic curve:
 
 [latexmath]
-.The secp256k1 elliptic curve equation
 ++++
 \begin{equation}
-{y^2 = (x^3 + 7)} \text(over) \mathbb{F}_p
+{y^2 = (x^3 + 7)} \text{over} \mathbb{F}_p
 \end{equation}
-
+++++
 or 
 
+[latexmath]
+++++
 \begin{equation}
 {y^2 \mod p = (x^3 + 7) \mod p}
 \end{equation}
 ++++
-where +p = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F+, a very large prime. 
 
+where +p = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F+, a very large prime. 
 
 The +mod p+ indicates that this curve is over a finite field of prime order +p+, also written as F(p). The curve looks like a pattern of dots scattered in two dimensions, which makes it difficult to visualize. However, the math is identical as that of an elliptic curve over the real numbers shown above.