C1: indices and quadratics Flashcards
a^m * a^n
a^(m+n)
a^m / a^n
a^(m-n)
(a^m)^n
a^mn
a^(m/n)
n√a^m
(a/b)^-n
(b^n)/(a^n)
√(a^2 * b)
a√b
Rationalise the denominator of a/√b
a/√b * √b/√b = (a√b)/b
Rationalise the denominator of 1/(a + √b)
1/(a + √b) * (a - √b)/(a - √b) = (a - √b)/(a^2 - b)
How do you complete the square?
factorise the coefficient of x^2 out of the first two terms
a(x^2 + bx/a) + c = 0
a(x - b/2a)^2 - (b/2a)^2 + c = 0
Give the quadratic formula.
x = (-b +- √b^2 - 4ac)/2a
Give the discriminant.
b^2 - 4ac
What information does the discriminant give?
if < 0, no solutions
if = 0, one solution
if > 0, two solutions
How do you solve quadratics in completed square form?
(x + a)^2 - b = 0
(x + a)^2 = b
x + a = +-√b
x = a + √b or x = a - √b
How do you solve quadratic inequalities?
find the points where x = 0
draw a graph
shade above/below as applicable
How do you solve simultaneous equations wherein one is linear and one quadratic?
rearrange the linear to make one unknown the subject
substitute into quadratic