Equation on slide 54 describes the

Equation on slide 54 describes the distance from the sun to Earth. Use Excel program to
calculate and plot this distance as a function of days. From the graph, find the maximum
and minimum value of the distance. When is it occurs? Is it sensible to assume that the
distance from the sun to Earth is constant? Comment on your result.

Equation 7 (page 62) is the relationship between the declination angle and the day of the
year. Use Excel program to obtain and plot the declination angle as a function of days.
From your calculation, when does the sun position directly above the equator? What
happens on that particular day? When is the declination angle maximum? When is the
declination angle minimum? What happen on those particular dates? Explain your result.