ABCD is a trapezium 9 cm
B
4
С
6.5 cm
6 cm
D
A
23 cm
Work out the size of angle CDA, giving your answer to 1 decimal place.

the rate at which total personal income was rising in the area in 1999 is $1,580,507,200 billion

Step-by-step explanation:

From the given information:

Let consider y to represent the number of years after 1999

Then the population in time (y) can be expressed as:

P(y) = 9400y + 924900

The average annual income can be written as:

A(y) = 1400y + 30388

The total personal income = P(y)  ×  A(y)

The rate at which the total personal income is rising is T'(y) :

T'(y) = P'(y)  ×  A(y)  + P(y)  ×  A'(y)

T'(y) = (9400y + 924900)' (1400y + 30388) + (9400y + 924900) (1400y + 30388)'

T'(y) = 9400(1400y + 30388) + (9400y + 924900) 1400

Since in 1999 y =0

Then:

T'(0) = 9400(1400(0) + 30388) + (9400(0) + 924900) 1400

T'(0) = 9400(30388) + (924900)1400

T'(0) = $1,580,507,200 billion

Therefore; the rate at which total personal income was rising in the area in 1999 is $1,580,507,200 billion