HW1-2 HW1-7 <br\> HW2-3 HW2-8 HW2-13 HW2-15 <br\> HW3-5 <br\> HW4-6(c) HW4-7(c) HW4-8(c) <br\> HW5-4 HW5-6 HW5-11 <br\> HW6-1 <br\> HW7-6