To find the first four terms of the sequence defined by a1 = 1 and an = 4 an-1, we will start by computing each term step by step:
- First term (a1): By the given condition, we have:
- a1 = 1
- Second term (a2): Using the formula an = 4 an-1, we calculate:
- a2 = 4 a1 = 4 × 1 = 4
- Third term (a3): Now we compute:
- a3 = 4 a2 = 4 × 4 = 16
- Fourth term (a4): Finally, we find:
- a4 = 4 a3 = 4 × 16 = 64
Thus, the first four terms of the sequence are:
- a1 = 1
- a2 = 4
- a3 = 16
- a4 = 64
In summary, the first four terms are: 1, 4, 16, and 64.