The number of spots on the surface of the sun varies periodically from 0 to about 100, with a period of approximately 11 years. There was a sunspot minimum in 1997. a. Determine an equation that can be used to estimate the number of sunspots during any year after 1997. b. Use your equation to predict the number of sunspots that would be seen on Jan 1,2043. c. Determine if there were any years in the 1970s with 50 sunspots.