AS Flashcards
What are the indices rules?
When should you complete the square?
When a quadratic equation will not factorise easily
How do you complete the square? (using x2 +yx + c)
Write in the form (x + y/2)2 -(y/2)2 + c
Complete the square of x2 + 6x + 7?
(x+3)2 -32 + 7
= (x+3)2 -2
Complete the square of 2x2 + 8x + 7?
2[x2 + 4x + 7/2]
= 2[(x+2)2 -22 + 7/2)
= 2[(x+2)2 - 1/2]
= 2(x+2)2 - 1
How woulkd you complete the square of -x2 + 4x + 5
= -1[x2 -4x -5]
Then complete as normal to get
-1(x-2)2 + 9
What is the quadratic formula?
What is the discriminant of the quadratic formula?
b2 - 4ac
What happens when b2 - 4ac > 0 ?
There are two real distinct roots
What happens when b2 - 4ac = 0 ?
There is one real root (repeated)
What happens when b2 - 4ac
No real roots
What are the inequality symbols?
Same for not equal to but circle not shaded in
How can you tell the line of symetry from completing the square?
(x + y)2 + c
Curve is left by y and up by c
What is a transformation of y = f(x-a)?
Transformation of the graph by (x+a,y)
What is the transformation of y = f(a) + b?
Graph is transformed by (x,y+b)
What is the transformation of y = af(x)?
Graph is strechted by scale factor a (parallel to y-axis)
(x,ay)
What is the transformation of y = f(ax)?
Transformation of graph by 1/a parallel to x axis
((1/a) x, y)