Formulas and Key concepts Flashcards
Higher degree polynomial e.g. 3x^4 - 48x^2 = 0
Sec.1.5
- Factorise
- Number in front of bracket equals 0
- Number inside bracket equals 0
- Solve both for x
Higher degree polynomial by grouping
- Split into two groups
- Find similar inside bracket
- Outside both brackets equal to form 1 bracket and then use the similar bracket and multiple together
- Set each bracket to 0 and solve
Can you square root a minus e.g. square root -3
No, it equals no solution
[a,b] means?
a and b are included, a <= x <= b, circles filled in
(a,b) means?
a and b are no included, a < x < b, circles hollow
Bounded is when?
Line together between two points -3 < x < 5
unbounded is when?
Line from point to infinity e.g. x < infinity
What do you do when you multiple an inequality with a minus number
switch the symbol
Solving double inequalities, what do you do?
- Get just x in the middle
- what ever you do on one side you do on the other
- what ever is left on each side of x, put into notation
- graph on number line
Solve absolute inequalities e.g. | x - 5 | < 2
- Put absolute in the middle and then the number 2 on right side and -2 on left
- solve
- notation
- Graph
Solve absolute inequalities e.g. | x + 3 | >= 7
- Make | x + 3 | <= -7 and >= 7
- solve both
- Notation with U
- graph
Test intervals of inqualities
- Find zeros
- write test in order
- for each test make x = a sensible number
- For
Pythagorus
a^2 + b^2 = c^2
Distance formula
SR (x2 - x1)^2 + (y2 - y1)^2
Mid point formula
(x1 + x2 / 2) , (Y1 + Y2 / 2)
Find Y int
Plug 0 into X and solve for Y
Find X int
Plug 0 into Y and solve for X
Testing for symmetry
- x axis = replace y with -y, should equal same equation
- y axis = Replace x with -x, should equal same equation
- Origin = replace both with minus
Equation of circle
(x-h)^2 + (y - k)^2 = r^2
(h,k) is centre
Equation of line and what each represents?
y = mx + b m = slope b = y int
Slope formula
Y2 - Y1 / X2 - X1 = M
Types of slopes
m = + , positive slope M = - , negative slope m = 0 , horizontal m = undefined , verticle
Point slope formula
y - y1 = m(x - x1)
How do we know if lines are parallel or perpendicular
parallel = same slope perpendicular = recipricol