Formulae not in booklets

Question 1

The area of a histogram box is proportional to

Answer 1

frequency

Question 2

Area of a histogram box=

Answer 2

k x frequency

Question 3

The frequency of a histogram box is proportional to

Answer 3

Frequency density x class width

Question 4

Frequency density=

Answer 4

k x frequency/ class width
or
area/ class width

Question 5

What are the formulae for the energy stored in a spring/ string/ rod?

Answer 5

= 1/2 x force x extension
= 1/2 x k x extension^2
= 1/2 x force^2/ k

Question 6

Area of integration

Answer 6

Between limits x1 to x2 integrate (y(x))dx

Question 7

Derivative of tanx

Answer 7

sec^2(x)

Question 8

Integral of tanx

Answer 8

ln|sec(x)| + c

Question 9

Derivative of sinx

Answer 9

Cosx

Question 10

Integral of sinx

Answer 10

-(- cosx)

Question 11

Derivative of secx

Answer 11

sec(x)tan(x)

Question 12

Arithmetic series

Answer 12

Sn= n/2 (2a + (n-1)d) or
Sn= n/2(a+l)

Question 13

Nth term of a geometric sequence

Answer 13

Un= ar^(n-1) where r= common ratio

Question 14

Geometric series

Answer 14

Sn= a(1-r^n)/ 1-r or
Sn= a(r^n- 1)/ r-1

Question 15

A geometric sequence is convergent if….

Answer 15

|r|<1

Question 16

Sum of a convergent geometric series

Answer 16

S(infinity)= a/(1-r)

Question 17

How do you know if a sequence is increasing or decreasing

Answer 17

Increasing: Un+1>Un
Decreasing: Un+1<Un
For all natural numbers

Question 18

How do you know if a sequence is periodic

Answer 18

Un+k= Un
Where k is the order of the sequence

Question 19

Interpolation formula e.g. Q1

Answer 19

Q1= value until interval + (difference between first and nth interval)/ (difference between first and last number in interval) × class width

Question 20

Integral of secx

Answer 20

secx x tanx