Graphs

Question 1

Midpoint

Answer 1

[(x₁ + x₂)/2 , (y₁ + y₂)/2]

Question 2

Gradient

Answer 2

dy/dx = m

Question 3

Perpendicular gradient

Answer 3

m₁ x m₂ = -1

Question 4

Equation of line

Answer 4

y - y₁ = m ( x - x₁ )

Question 5

Discriminant: 2 roots

Answer 5

b² - 4ac > 0

Question 6

Discriminant: 1 or repeated roots

Answer 6

b² - 4ac = 0

Question 7

Discriminant: No real roots

Answer 7

b² - 4ac < 0

Question 8

Form of circle equaion

Answer 8

( x + a )² + ( y + b )² = r²