A book is launched up a frictionless ramp that has an angle of 35 degrees to the horizontal.If the Book's initial speed is 2.0 m/s^2 , how far up the ramp does it slide?

I got 15.24. Any help would be greatly appreciated.

15.24 in what units?

The units of your initial speed are wrong. It has to be in m/s, not m/s^2.

This problem is most easily done using conservation of energy. You can use that method because it is frictionless.

The book will increase its potential energy by an amount equal the initial kinetic energy. Its elevation will then increase by H = V^2/(2 g)
The distance up the ramp will be
H/sin 35.

I do not agree with your answer.