If (f(x) = begincases sin x, & 0 leq x leq π/4 cos x, & π/4 leq x < π/2 endcases), then show that (f(x) sim 8/π cos(π/4)(sin x/1.3 + sin 3x/5.7 + sin 10x/9.11 + ⋅)).
a) Using scaling method and Fourier series
b) Using Taylor series
c) Using complex analysis
d) No such relation exists
