Agricultural scientists have found that the amount of time a crop needs

to reach peak maturity is closely related to the temperature during its growing

time. This relationship is expressed in terms of the number of growing degree days,

determined as follows: when the average temperature T on a day is above a certain

threshold r (specific to each crop), the day amounts to (T- r) growing degree days.

Let Tt, t = 1,......, 365, denote the average temperature on day t of the year. If the

crop is planted late on day p of the year, then the total number of growing degree

days during a subsequent period of n days (with temperature above threshold) is

D = (T_p+1 - r) + (T_p+2 - r) +..... + (T_p+n - r)

The average temperature in Iowa, USA, can be approximated by the function

T_t= 10 - 15cos[(t - 17)2pi/365] Degrees Celcius

The threshold temperature for peas is r = 4 C and they require 800 growing degree

days to reach maturity and be ready for harvesting.

(a) Write a MATLAB program to plot the temperature T_t against t, t = 1,...,365, and hence find the period of the year for which the temperature is above the threshold for peas.

(b) A farmer in Iowa plants a crop of peas late on day 90 and wants to know when

it will be ready for harvesting. Write a MATLAB program to find the number

of growing degree days Dn during a subsequent period of n days, where n

ranges from 1 to 100. Plot Dn against n, and from the graph determine how

many days it will take for the peas to be ready for harvesting.

REQUEST showing of Programming since I am really having trouble with how to apply this to MATLAB