Finding Limits of Sums of Terms w/ Diff Limits

Sun God
Messages
7
Reaction score
0
For instance:

1/(e^.5t) + 1/(e^-7t)

As t grows larger, the left term goes to 0, but the right term goes to infinity.

Would I be correct in saying that the limit of the sum is infinity because the (absolute value of the) coefficient of t in the term that tends to infinity is larger than the coefficient of t in the term that tends to 0?

What if both t's had the same coefficient?
 
Physics news on Phys.org
It doesn't matter what the coefficients are. If \{a_n\} and \{b_n\} are any two sequences such that \lim_{n\to\infty} a_n= \infty and \lim_{n\to\infty}b_n= 0, then \lim_{n\to\infty} (a_n+ b_n)= \infty.

More generally, if \lim_{n\to\infty} a_n= A and \lim_{n\to\infty}b_n= 0, then \lim_{n\to\infty} (a_n+ b_n)= A.
 
Last edited by a moderator:
Fixed you LaTeX script. There were [ itex] tags mixed in with [ math] tags.
HallsofIvy said:
It doesn't matter what the coefficients are. If \{a_n\} and \{b_n\} are any two sequences such that \lim_{n\to\infty} a_n= \infty and \lim_{n\to\infty}b_n= 0, then \lim_{n\to\infty} (a_n+ b_n)= \infty.

More generally, if \lim_{n\to\infty} a_n= A and \lim_{n\to\infty}b_n= 0, then \lim_{n\to\infty} (a_n+ b_n)= A[/itex].
 
Thanks, Mark
 
Back
Top