f sxd −

1 1 x 2 x2 x

Find the most general antiderivative of the function.
(Check your answer by differentiation.)

==21.
dy dt − t 2 1 1, t > 0, y − 6 when t − 0 Solve the initial-value problem.
==22.
dy dt − 1 1 2 t , t . 0, y − 5 when t − 1 Solve the initial-value problem.
==23.
dP dt − 2e3t, t > 0, Ps0d − 1 Solve the initial-value problem.
==24.
dm dt − 100e20.4t, t > 0, ms0d − 50 Solve the initial-value problem.
==25.
dr d
− cos  1 sec  tan , 0 ,  , y2, rsy3d − 4 Solve the initial-value problem.
==26.
dy dx − x2 1 1 1 1 x2 1 1 , y − 0 when x − 1 Solve the initial-value problem.
==27.
du dt − st 1 2 st , t . 0, us1d − 5 Solve the initial-value problem.
==28.
dv dt − e2ts1 1 e2td, t > 0, vs0d − 3 Solve the initial-value problem.