12.3.6 Evaluate [ ( 2ti + 1 + 1 ) dt 12.3.7 Evaluate 12.3.8 Evaluate ( sec ? ti + 1 + 12 ) at 12.3.9 Evaluate 1 ( 8ti + tj - k) at 0 12.3.10 Evaluate It/ 2 [(acost)i+ (asint)j + k] dt 12.3.11 Find r(t) that satisfies the initial condition r'(t) = 4e2ti + 3etj, r(0) = 21 12.3.12 Find r(t) that satisfies the initial condition T' (t) = it=]+=k, r(1) = 21