fixed a comment

Author: SakiTakamachi

ext/bcmath/libbcmath/src/div.c

@@ -142,18 +142,13 @@ static inline void bc_standard_div(
 	 * Since B = 10^b, the formula becomes:
 	 * MAX_E = (n2_high * B * (B^k - 1)) / (n2_high * (n2_high * B^k + B^k - 1))
 	 * MAX_E = (10^x * 10^b * ((10^b)^k - 1)) / (10^x * (10^x * (10^b)^k + (10^b)^k - 1))
-	 * MAX_E = (10^(x + b) * (10^(k * b) - 1)) / (10^(2x + k * b) + 10^(x + k * b) + 10^x)
-	 * MAX_E = (10^(x + b) * (10^(k * b) - 1)) / (10^(x + k * b) * (10^x + 1) + 10^x)
 	 *
-	 * Now let's make an approximation. Remove -1 from the numerator and +1 from the denominator. Approximate
-	 * the numerator to be large and the denominator to be small, such that MAX_E is less than this expression.
-	 * MAX_E = (10^(x + b) * (10^(k * b) - 1)) / (10^(x + k * b) * (10^x + 1) + 10^x)
-	 * MAX_E < (10^(x + b) * 10^(k * b)) / (10^(x + k * b) * 10^x + 10^x)
-	 * MAX_E < (10^(x + k + 2b)) / (10^x * (10^(x + k * b) + 1))
+	 * Now let's make an approximation. Remove -1 from the numerator. Approximate the numerator to be
+	 * large and the denominator to be small, such that MAX_E is less than this expression.
+	 * Also, the denominator "(10^b)^k - 1" is never a negative value, so delete it.
 	 *
-	 * Approximate again and remove +1 in the denominator
-	 * MAX_E < 10^(x + k + 2b) / (10^x * (10^(x + k * b) + 1))
-	 * MAX_E < 10^(x + k + 2b) / (10^x * 10^(x + k * b))
+	 * MAX_E = (10^x * 10^b * ((10^b)^k - 1)) / (10^x * (10^x * (10^b)^k + (10^b)^k - 1))
+	 * MAX_E < (10^x * 10^b * (10^b)^k) / (10^x * 10^x * (10^b)^k)
 	 * MAX_E < 10^b / 10^x
 	 * MAX_E < 10^(b - x)
 	 *