3. Consider a material subject to a uniform flow field characterized by L=0000000. By using F(t)=k=0k!1(Lt)k show that the deformation gradient tensor in this case can be written as F(t)=costsint0sintcost0001. (Hint: You can expand the Taylor series of F(t) to k=3 and compare the Fij terms with the corresponding Taylor series of cost and sint.)