Pure exams 3

Question 1

Completing the square

Answer 1

x^2+bx = (x+b)^2 - ((b/2)^2

ax^2+bx+c = a(x + (b/2a))^2 + (c - (b^2/4a)

Question 2

See series and sequences eqns and ensure know proof for sum of geo and ari

Answer 2

See series and sequences eqns

Question 3

discriminant and what shows

Answer 3

b^2-4ac
If b^2-4ac >0 there are 2 real solutions
If b^2-4ac =0 there is 1 real repeated root
If b^2-4ac <0 there are no real roots