12.3.6 Evaluate (2t^+^+k^)dt 12.3.7 Evaluate (t1^+^t23k^)dt 12.3.8 Evaluate (sec2t^+1+t21^)dt 12.3.9 Evaluate 01(8t^+t^k^)dt 12.3.10 Evaluate 0/2[(acost)^+(asint)^+k^]dt 12.3.11 Find r(t) that satisfies the initial condition r(t)=4e2t^+3et^,r(0)=2^ 12.3.12 Find r(t) that satisfies the initial condition r(t)=1+t21^+t21^+t1k^,r(1)=2^