Recurrence Check 8775Fd
1. **Problem Statement:**
Show that the sequence $\{a_n\}$ is a solution of the recurrence relation
$$a_n = -3a_{n-1} + 4a_{n-2}$$
for the given sequences:
2. **Recurrence Relation:**
The relation states that each term $a_n$ depends on the two previous terms $a_{n-1}$ and $a_{n-2}$ by the formula:
$$a_n = -3a_{n-1} + 4a_{n-2}$$
3. **Check each sequence:**
**a) $a_n = 0$**
- Substitute into the recurrence:
$$0 = -3 \cdot 0 + 4 \cdot 0 = 0$$
- Holds true for all $n$.
**b) $a_n = 1$**
- Substitute:
$$1 \stackrel{?}{=} -3 \cdot 1 + 4 \cdot 1 = -3 + 4 = 1$$
- Holds true for all $n$.
**c) $a_n = (-4)^n$**
- Substitute:
$$(-4)^n \stackrel{?}{=} -3(-4)^{n-1} + 4(-4)^{n-2}$$
- Factor right side:
$$= (-4)^{n-2}(-3(-4) + 4) = (-4)^{n-2}(12 + 4) = 16(-4)^{n-2}$$
- Left side:
$$(-4)^n = (-4)^2 \cdot (-4)^{n-2} = 16(-4)^{n-2}$$
- Both sides equal, so true.
**d) $a_n = 2(-4)^n + 3$**
- Substitute:
$$2(-4)^n + 3 \stackrel{?}{=} -3[2(-4)^{n-1} + 3] + 4[2(-4)^{n-2} + 3]$$
- Expand right side:
$$= -6(-4)^{n-1} - 9 + 8(-4)^{n-2} + 12 = -6(-4)^{n-1} + 8(-4)^{n-2} + 3$$
- Factor powers:
$$-6(-4)^{n-1} + 8(-4)^{n-2} = (-4)^{n-2}(-6(-4) + 8) = (-4)^{n-2}(24 + 8) = 32(-4)^{n-2}$$
- Left side:
$$2(-4)^n + 3 = 2 \cdot 16 (-4)^{n-2} + 3 = 32(-4)^{n-2} + 3$$
- Both sides equal, so true.
**Final conclusion:** All given sequences satisfy the recurrence relation.