Using the sequential definition of uniform continuity to show $sin(x)$ is uniformly continuous on $mathbb{R}$











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I want to show $sin(x)$ is uniformly continuous on $mathbb{R}$. Let ${a_{n}}$ and ${b_{n}}$ be sequences such that $lim_{ntoinfty}[b_{n} - a_{n}] = 0$. Then, we need to show $lim_{ntoinfty} |sin(b_{n}) - sin(a_{n})| = 0$. But, I cannot prove this equality. Can someone please help me?










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    Mean Value Theorem.
    – Kavi Rama Murthy
    58 mins ago















up vote
0
down vote

favorite












I want to show $sin(x)$ is uniformly continuous on $mathbb{R}$. Let ${a_{n}}$ and ${b_{n}}$ be sequences such that $lim_{ntoinfty}[b_{n} - a_{n}] = 0$. Then, we need to show $lim_{ntoinfty} |sin(b_{n}) - sin(a_{n})| = 0$. But, I cannot prove this equality. Can someone please help me?










share|cite|improve this question


















  • 2




    Mean Value Theorem.
    – Kavi Rama Murthy
    58 mins ago













up vote
0
down vote

favorite









up vote
0
down vote

favorite











I want to show $sin(x)$ is uniformly continuous on $mathbb{R}$. Let ${a_{n}}$ and ${b_{n}}$ be sequences such that $lim_{ntoinfty}[b_{n} - a_{n}] = 0$. Then, we need to show $lim_{ntoinfty} |sin(b_{n}) - sin(a_{n})| = 0$. But, I cannot prove this equality. Can someone please help me?










share|cite|improve this question













I want to show $sin(x)$ is uniformly continuous on $mathbb{R}$. Let ${a_{n}}$ and ${b_{n}}$ be sequences such that $lim_{ntoinfty}[b_{n} - a_{n}] = 0$. Then, we need to show $lim_{ntoinfty} |sin(b_{n}) - sin(a_{n})| = 0$. But, I cannot prove this equality. Can someone please help me?







real-analysis inequality uniform-convergence uniform-continuity






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asked 1 hour ago









joseph

385




385








  • 2




    Mean Value Theorem.
    – Kavi Rama Murthy
    58 mins ago














  • 2




    Mean Value Theorem.
    – Kavi Rama Murthy
    58 mins ago








2




2




Mean Value Theorem.
– Kavi Rama Murthy
58 mins ago




Mean Value Theorem.
– Kavi Rama Murthy
58 mins ago










1 Answer
1






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3
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By the mean value theorem:



$sin(b_{n}) - sin(a_{n})= cos (t_n)(b_n-a_n)$ with $t_n$ between $a_n$ and $b_n$.



Can you proceed ?






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  • i understand now, thanks.
    – joseph
    52 mins ago











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
3
down vote













By the mean value theorem:



$sin(b_{n}) - sin(a_{n})= cos (t_n)(b_n-a_n)$ with $t_n$ between $a_n$ and $b_n$.



Can you proceed ?






share|cite|improve this answer





















  • i understand now, thanks.
    – joseph
    52 mins ago















up vote
3
down vote













By the mean value theorem:



$sin(b_{n}) - sin(a_{n})= cos (t_n)(b_n-a_n)$ with $t_n$ between $a_n$ and $b_n$.



Can you proceed ?






share|cite|improve this answer





















  • i understand now, thanks.
    – joseph
    52 mins ago













up vote
3
down vote










up vote
3
down vote









By the mean value theorem:



$sin(b_{n}) - sin(a_{n})= cos (t_n)(b_n-a_n)$ with $t_n$ between $a_n$ and $b_n$.



Can you proceed ?






share|cite|improve this answer












By the mean value theorem:



$sin(b_{n}) - sin(a_{n})= cos (t_n)(b_n-a_n)$ with $t_n$ between $a_n$ and $b_n$.



Can you proceed ?







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered 57 mins ago









Fred

41.8k1642




41.8k1642












  • i understand now, thanks.
    – joseph
    52 mins ago


















  • i understand now, thanks.
    – joseph
    52 mins ago
















i understand now, thanks.
– joseph
52 mins ago




i understand now, thanks.
– joseph
52 mins ago


















 

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