LINEAR EQUATION
summary :

gradient form	y = mx + c
general form	Ax + By + C = 0
intercept form	x/a + y/b = 1

QUADRATIC EQUATION
summary :

general form	y = ax2 + bx + c
perfect square form	y = a(x+p)2 + q

BASIC POLYNOMIALS
( a + b ) = a² + 2ab + b²
( a - b ) = a² - 2ab + b²
( a² - b² ) = ( a + b )( a - b )

BASIC TRIGONOMETRY
a = adjacent
o = opposite
h = hypotenuse
Pythagoras Theorem :      h² = o² + a²
remember Mr Soh Cah Toa      (    Sin θ = o / h      Cos θ = a / h      Tan θ = o / a    )

	0o	30o	45o	60o	90o
sin	0	½	≈ 0.707	≈ 0.866	1
cos	1	≈ 0.866	≈ 0.707	½	0
tan	0	≈ 0.577	1	≈ 1.732	∞

remember All Sinful people Telan Crocodile

Sin is +	All are +
Tan is +	Cos is +

EXPONENTS
a^m × aⁿ = a^m+n
a^m ÷ aⁿ = a^m-n
a^m × b^m = (a×b)^m
a^m ÷ b^m = (a÷b)^m
(a^m)ⁿ = a^m×n

LOGARITHM
log (x^a) = a log (x)
log (xy) = log (x) + log (y)
log (x/y) = log (x) - log (y)
log_ST = log_aT / log_aS

BASIC STATISTICS
measures of central tendency :

	ungroupd data	grouped data
mean	x = ( ∑ xi ) ÷ N	x = ( ∑ fixi ) ÷ ( ∑ fi )
mode	observation that occurs the most	frequency distribution table ------> modal class histogram ---------------------------> mode
median	modd = [(N+1)/2]th observation meven = [ (N/2)th observation + (N/2 + 1)th observation ] ÷ 2	cumulative frequency table & m = L + [ (N/2 - F)÷ fm ] C ogive & (N/2)th observation

measures of dispersion :

	ungroupd data	grouped data
range	largest observation - smallest observation	midpoint of highest class - midpoint of lowest class
interquartile range	SMILE !	Q1 = L1 + [ ¼N - F1) ÷ fQ1 ] C Q3 = L3 + [ ¾N - F3) ÷ fQ3 ] C
variance	σ2 = [ ∑(xi-x)2 ] ÷ N = [ ( ∑xi2 ) ÷ N ] - x2	σ2 = [ ∑fi(xi-x)2 ] ÷ ∑ fi = [ ( ∑fixi2 ) ÷ ∑ fi ] - x2
standard deviation	σ	σ

effects of data being changed uniformly :

	measures of central tendency	measures of dispersion
each data is added by k	new mean = original mean + k new mode = original mode + k new median = original median + k	range DOES NOT CHANGE interquartile range DOES NOT CHANGE variance DOES NOT CHANGE standard deviation DOES NOT CHANGE
each data is multipied by k	new mean = original mean × k new mode = original mode × k new median = original median × k	new range = original range × k new interquartile range = original interquartile range × k new variance = original variance × k2 new standard deviation = original standard deviation × k

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