Science:Math Exam Resources/Courses/MATH102/December 2013/Question A 07/Statement

The number of sunspots (solar storms on the sun) varies with a period of roughly 11 years reaching a high of 120 and a low of 0 sunspots detected. A peak of 120 sunspots was detected in the year 2000. Which of the following trigonometric functions could be used to approximate this cycle?

(a) $N=60+120\sin \left({\frac {2\pi }{11}}(t-2000)+{\frac {\pi }{2}}\right)$

(b) $N=60+60\sin \left({\frac {11}{2\pi }}(t+2000)\right)$

(c) $N=60+60\cos \left({\frac {11}{2\pi }}(t+2000)\right)$

(d) $N=60+60\sin \left({\frac {2\pi }{11}}(t-2000)\right)$

(e) $N=60+60\cos \left({\frac {2\pi }{11}}(t-2000)\right)$