# Math Help - Not sure of answers

1. ## Not sure of answers

1) Find a formula for the nth term of the sequence: 0,-1,0,1,0,-1,0,1,0,-1,0,1 -------- I got an= sin (nn)

2) Find limit of sequence if it converges:
an = 3-8n+4n^4/(3n^4+9n^3-2) -------- I got 4/3

3) Find limit of sequence if it converges; an = (3/n) subscript(3/n) --- I got 0.

4) Find limit of sequence if it converges; an= 5+ (-1)^n / 5 ---- I got 1

5) Determine if the sequnce is decreasing/non-decreasing/bound/unbounde… :
an = (4n+1)/(n+1) ----- I got nondecreasing, bounded

If the answers aren't right, could someone explain/show what the correct answer is?

2. Originally Posted by MathFeed

1) Write the first 4 elements of the sequence: (n+1)/(3n-1)
I got -1,1,3/5,1/2 not quite

2) Find a formula for the nth term of the sequence: 0,-1,0,1,0,-1,0,1,0,-1,0,1 -------- I got an= sin (nn) If n starts at 1, then $-\sin[(n-1)\frac{\pi}{2}]$

3) Find limit of sequence if it converges:
an = 3-8n+4n^4/(3n^4+9n^3-2) -------- I got 4/3 good

4) Find limit of sequence if it converges; an = (3/n) subscript(3/n) --- I got 0.
5) Find limit of sequence if it converges; an= 5+ (-1)^n / 5 ---- I got 1 Diverges

6) Determine if the sequnce is decreasing/non-decreasing/bound/unbounde… :
an = (4n+1)/(n+1) ----- I got nondecreasing, bounded

If the answers aren't right, could someone explain/show what the correct answer is?
...

3. Could you explain 5 & 6?

4. Originally Posted by MathFeed
Could you explain 5 & 6?
Sure.

5. Assume n even, then take the limit. Assume n odd, then take the limit. You'll see that one goes to $\infty$, while the other goes to $-\infty$

6. is correct. if you take the derivative, note that the sequence is positive for all x>1. Also, the limit of the sequence is 4.