Write
(i) the coefficient of x3 in x+3x2−5x3+x4
(ii) the coefficient of x in √3−2√2x+6x2
(iii) the coefficient of x2 in 2x−3+x3
(iv) the coefficient of x in 38x2−27x+16
(v) the constant term in π2x2+7x−25π
Find the coefficient of x15 in (x3+x6+x9+...........)(x2+x4+x6+...........)(x+x2+x3+..........)