3. The cosine function: The cosine function can be evaluated by the following infinite series X X Cosx=1 + 2! 4! 6! (a) Write a function that needs as an input the number of terms n of the cosine series and the value of x and then it calculates the series up to the n'" term. Make sure that the function does the following: (i) calculates and stores the value of the true percent relative error for each value of k from k = 1 to k = n where n is the number of terms given by the user. (ii) plots the true percent relative error for each value of k from k = 1 to k = n. it labels the x- axis, the y-axis and adds a legend. The plot has to be logarithmic on both x and y axes (i.e. log-log plot which can be done by using loglog instead of plot) (iii) times itself using tic; toc; (b) Run the function for the case x= n and n=170 and report the final plot, and the time of the calculation. (C) From your log-log plot in part (b), how many terms are enough to reach percent relative error less than 10-13 %. (d) If you look at the series, there is an issue in using 200 terms or more. What is the issue