A) Let P(t) be written as P(t) = a cos[b(t - d)] + c
The minimum Pmin and the maximum Pmax of P(t) are given.
Pmin = 4
Pmax = 20
c = (Pmax + Pmin) / 2 = (20 + 4) / 2 = 12
|a| = (Pmax - Pmin) / 2 = (20 - 4) / 2 = 8
We now need to find the number of days t after January 1st at which P(t) is maximum by counting the days of the months from January to May and adding 21 days in June.
t = 31 + 28 + 31 + 30 + 31 + 21 = 172
We now use the period to find b (b > 0) as follows
period = 365 = 2π / b
hence b = 2π / 365
A cosine function without shift has a maximum at t = 0. P(t) has a maximum at t = 172. We can model P(t) by a cos(x) function shifted by 172 to the right as follows:
P(t) = 8 cos[(2π / 365)(t - 172)] + 12
check that P(t) is maximum at t = 172: P(172) = 8 cos[(2π / 365)(172 - 172)] + 12 = 8 cos[(0)] + 12 = 20
b) The graph of P(t) is shown below.

perfect

Step-by-step explanation:

the system of inequity is

step-by-step explanation:

from the given graph it is noticed that we have two related lines. one is solid and another is dashed.

if a line passing through two points, then the equation of line is

the solid line passing through the points (0,4) and (4,0).

the related equation of solid line is .

similarly, find the related equation of dashed line. the dashed liune passing through the points (0,0) and (3,1).

the related equation of dashed line is

from the given graph it is noticed that the point (0,1) lies on the shaded region, therefore the point (0,1) must be satisfied by the related equations.

check the related equations by the point (0,1).

this statement is true if the sign of inequality is < instead of equality. since it is an solid line therefore the sign of inequality will be . the required inequality is

similarly, check the second related equation.

it is a dashed line, so this statement is true if the sign of inequality is > . the required inequality is

answer: 0,6

step-by-step explanation:

this would make it the y intercept.