1) for the first ans, ( equation of the curve ) c= -7 2)tan 2x = 3 , x=-54.2 , 35.8 for the other trigonometry , x= 7/12 pie , 11/12 pie 3) for the AP : i) 15th day = 130km ii) on 20th may for the gp i) r = 1/2 , a=16 ii) sum to infinity =30 4) for the binomial, n=6 , coefficient x^2 = 5.25 or 21/4