$$\sum_{ｎ＝１}^{\infty}　\frac{ ｎ }{ ８ｎ^{３}＋６ｎ^{２}－７ }$$　ｗｈｉｃｈ　ｔｅｓｔ　ｃａｎ　ｂｅ　ｕｓｅｄ　ｔｏ　ｓｈｏｗ　ｔｈｅ　ｓｅｒｉｅｓ　ｃｏｎｖｅｒｇｅｓ？

Question

zzr0ck3r · Answer

compare with 1/n^2

zzr0ck3r · Answer

n/(8n^3+6n^2-7) <= 1/n^2 and 1/n^2 converges by p series thus by comparison...

anonymous · Answer

Ｓｏ　ｔｈｅ　ｐ　ｓｅｒｉｅｓ　ｔｅｓｔ　ｉｓ　ｔｈｅ　ｂｅｓｔ　ｏｎｅ　ｔｏ　ｕｓｅ？

zzr0ck3r · Answer

no comparison test, is the test being used.

anonymous · Answer

ｏｈ，　ｉｔ＇ｓ　ａｓｋｉｎｇ　ｗｈｉｃｈ　ｉｓ　ｔｈｅ　ｂｅｓｔ　ｏｎｅ　ｔｏ　ｕｓｅ？

zzr0ck3r · Answer

comparison test is the answer

zzr0ck3r · Answer

do you know what the comparison test is?

anonymous · Answer

ｔｈｅ　ｌｉｍｉｔ　ｃｏｍｐａｒｉｓｏｎ　ｔｅｓｔ，　ｙｏｕ　ｓｅｔ　ｔｈｅ　ｎ　ｔｏ　ｉｎｆｉｎｉｔｙ　ａｎｄ　ｓｅｅ　ｗｈｅｒｅ　ｉｔ　ｇｏｅｓ？

zzr0ck3r · Answer

we have sum(a_n) 
if a_n <= b_n for all n and sum(b_n) converges then sum(a_n) converges
and since sum(1/n^2) converges, so does your sum(a_n)

zzr0ck3r · Answer

where a_n = n/(8n^3....)

anonymous · Answer

ｏｈ，　ｏｋ．　Ｔｈａｎｋ　ｙｏｕ　；）

zzr0ck3r · Answer

np

anonymous · Answer

DUUUUUUDDE.....what happened to your keyboard? o.o

anonymous · Answer

Ｉｍ　ｕｓｉｎｇ　ｉｔ　ｒｉｇｈｔ　ｎｏｗ　：Ｄ

anonymous · Answer

das so weird o.o