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Calculus/Limits and continuity

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Question
Hi, Paul.
I´m father the universitary son.
I like help to answer the problem the calculus the mi son
sorry,my english it's no good

The problem is.
Lim
x-> 1   (Sen (pi x))/(x(x+1))

your truly
Mario Monge
Arica-Chile


Answer
Questioner:   Mario Monge
Category:  Calculus
 
Subject:  finding limit
Question:  Hi, Paul.
I´m father the universitary son.
I like help to answer the problem the calculus the mi son
sorry,my english it's no good

The problem is.
Lim
x-> 1   (Sen (pi x))/(x(x+1))

your truly
Mario Monge
Arica-Chile
.......................................
Hola, Mario,

If this is your question:

      sin(pi x)
lim   -----------
x->1    x(x+1)

then it is really not a problem.  The denominator,  x(x+1), does not become zero at the limit, x=1, so this function is CONTINUOUS, and we can just substitute  x = 1:

      sin(pi x)      sin(pi)      0
lim   ----------- =  -------- = ------- = 0
x->1    x(x+1)        1(1+1)       2

I think you may have mistyped something, however.  Check your example again.  Was it:

      sin(pi x)
lim   -----------
x->1    x(x-1)


If it was, then we have more work to do.

Calculus

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Paul Klarreich

Expertise

All topics in first-year calculus including infinite series, max-min and related rate problems. Also trigonometry and complex numbers, theory of equations, exponential and logarithmic functions. I can also try (but not guarantee) to answer questions on Analysis -- sequences, limits, continuity.

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I taught all mathematics subjects from elementary algebra to differential equations at a two-year college in New York City for 25 years.

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(See above.)

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