Integrating with a TI89?

When I integrate with my Ti89 for an indefinite integral with respect to x of cosx[integral cosxdx], it gives me a different answer in degree mode than in radian. In radian it gives me the correct answer, sinx. But in degree mode it multiplies the answer by 180/pi. Does anyone know why? Its been giving me wrong answers because of this problem. What it does is even though it spits the answer out as sinx180/pi it will multiply by 180/pi again when evaluating when doing definite integrals such as [integral cosxdx,x,0,60degrees].