sum of the roots
-b/a
product of the roots
c/a
vertex formula
x = -b/2a
mid-point formula
((x1+x2)/2 , (y1+y2)/2 )
vertex form
y = a(x-h)² + k
complimenting rule
sin (x) = cos (90-x)
cos (x) = sin (90-x)
arc length
arc length = part of the circumference
2πr * angle/360
sector area
sector area = part of the area
πr² = angle/360
equations of a circle on the coordinate plane
(x-h)² + (y-k)² = r²
density formula
density = mass/volume