4.00 points) Let f(:1:) = a1 sin m+a2 sin 233+. ~ ~+nn sin nm, where (11.412, . . . , an are real numbers and where n is a. positive integer. Given that I f(.1:)| S |sin :1:| for all real 3:, prove that |a1 + 20.2 + - - - + nan| 5 1