Suppose x is an n-vector. the associated vector of differences is the (n−1)-vectordgivenbyd=(x2 −x1,x3 − −xn−1). expressdintermsofx using vector operations (e. g., slicing notation, sum, difference, linear combinations, inner product). the difference vector has a simple interpretation when x represents a time series. for example, if x gives the daily value of some quantity, d gives the day-to-day changes in the quantity.

from the figure we get,

the x axis shows   the months and,

the y-axis shows the number of satisfied customer.

each line or each cell in upward direction (y-axis) shows 500.

the appropriate scale for the y - axis is: -

a = 2000 customers

b = 4000 customers

c = 6000 customers

d = 8000 customers

e = 10000 customers

f = 12000 customers

g = 14000 customers

okay..i will pick 8!

secant-secant formula:

(whole secant) x (external part) =           (whole secant) x (external part)

(8+y-2) *8=                                           (y+4+6) *6

(y+6)*8 = (y+10) *6

distribute

8y+48 = 6y +60

subtract 6y from each side

2y +48 = 60

subtract 48 from each side

2y = 12

divide by 2

y = 6

sv =     (y+4+6)

sv   = 6+4+6

sv = 16