kak tolong bantu tugas ini!! b dan c

b. Un= 3n-2. c.Un=1/2(n²-1)
U1 = 3.1 - 2 |U1=1/2(1²-1)
=3-2 |=1/2.0
=1. |=0
U2=3.2 - 2 |U2=1/2(2²-1)
=6-2. |=1/2.3
=4. |=3/2
U3=3.3 - 2. |U3=1/2(3²-1)
=9-2. |=1/2.8
=7. |=4
U4=3.4 - 3. |U4=1/2(4²-1)
=12 - 3. |= 1/2.15
= 9. |= 15/2
U5=3.5 - 3. |U5=1/2(5²-1)
=15 - 3. |=1/2.24
=12. |= 12
Sorry berantakan udah ak kasih batas |