∫π20 sin3x2 dxcos3x2+sin3x2= [Roorkee 1989; BIT Ranchi 1989]
π4
Let I=∫π20sin3x2 dxcos3x2+sin3x2 ⋯(i)
=∫π20sin32(π2−x)cos32(π2−x)+sin32(π2−x)dx
=∫π20cos3x2 dxsin3x2+cos3x2 ⋯(ii)
Adding (i) and (ii), we get I=12∫π20 1dx=12[x]π20=π4