equations Flashcards
volume of a cone
1/3 * π * r squared * h
surface area of a cone
( π * r squared ) + ( π * r * l)
volume of a pyramid
1/3 * area of base * height
volume of a cylinder
π * r squared * h
surface area of a cylinder
( 2* π * r squared ) + ( π * d * h )
volume of a sphere
4/3 * π * r cubed
surface area of a sphere
4 * π * r squared
a^2 =
b^2 + c^2 - 2bcCosA
area of a triangle (no right angle)
1/2 * abSinC
area of a sector of a circle
theta/360 * π * r squared
sum of interior angles in a polygon
(n-2) * 180
size of one exterior angle of a polygon
360/n
pressure =
force/area
decay (also known as depreciation - the opposite is compound interest) =
original amount( 1 - (rate of decay/100))^time
simple interest =
(original amount * rate of growth * time)/100
length of an arc of a sector =
(theta/360) * 2 * π * r
Addition formula (probability)
P (A U B) = P(A) + P(B) - P(A N B)
Probability of A given B has happened
P(A|B) = P(A N B)/ P (B)
Length of a space diagonal in a cuboid/cube
d = sqrt (a^2 + b^2 + c^2)
1 litre = how many cl
100cl
1 cl = how many ml
10ml
5 miles = ?km
8km
1 foot = ?inches
12 inches
1 foot = ?cm
30cm
1m^2 = ?cm^2
10,000 cm^2
1cm^2 = ? mm^2
100 mm^2
area of a kite
half product of its diagonals
matrix transformation for an enlargement of scale factor k with centre (0,0)
k 0
0 k
matrix transformation for an identity (stays the same)
1 0
0 1
if composite transformation A is followed by transformation B what do you do
multiply the matrices in order BA
how to tell if the point on a curve is the maximum
gradient goes from positive to negative
d^2y/dx^2 <0
how to tell if the point on a curve is the minimum
goes from negative to positive
how do you know if a function is increasing
dy/dx is greater than 0
what is the equation of a circle with radius r and centre (a,b)
(x-a)^2 + (y-b)^2 = r^2
there are two equations of the line. one is y = mx + c. what is the other one
y2 - y1 =m(x2 - x1)
frequency density =
frequency / class width
amount in sample =
(group number/total) * sample size
percentage change =
(difference/original) * 100
