how do I can create a list of the first interval such as [-10+Sin [k], 10+Sin [K]]

Question

A (k) =the closed interval [-10+Sin [k], 10+Sin [k]] How do I can create a list of the first 20 of such interval The find the intersection of the first 14 of them

Is k integer? Use Range and IntervalIntersetcion[] – Dr. belisarius Dec 01 '13 at 17:01 — Dr. belisarius, Dec 01 '13 at 17:01

J. W. Perry · Answer 1 · 2013-12-01T18:07:19.527

2

The code

ak = N[Table[Interval[{-10 + Sin[k], 10 + Sin[k]}], {k, 1, 20}]];

computes the first 20 as intervals. Remove the N[ ] wrapper for the exact values. You can then compute the intersection of the first 14 as closed intervals with

IntervalIntersection @@ ak[[1;;14]]

Finally this is the correct intersection: Interval[{-9.00939, 9.00001}]

edited Dec 01 '13 at 18:07

answered Dec 01 '13 at 17:02

J. W. Perry

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What's @ means? ? – mais Dec 01 '13 at 17:14
@Nana @@ -Apply. Difference between @ and @@. – Kuba Dec 01 '13 at 17:14
.. thank you :-) – mais Dec 01 '13 at 17:18
I see the problem 1 sec – J. W. Perry Dec 01 '13 at 17:20
I'm really confuse now... what is the corect code in this case? – mais Dec 01 '13 at 17:21
{-9.15853, 10.8415} – mais Dec 01 '13 at 17:24
Just wait while I fix this – J. W. Perry Dec 01 '13 at 17:24
Sorry about that. You're good to go. – J. W. Perry Dec 01 '13 at 18:02

score 2 · Answer 2 · answered Dec 01 '13 at 17:59

2

c = IntervalIntersection @@ (Array[ Interval[{-10 + Sin[#], 10 + Sin[#]}] &, {20}][[;; 14]])

Graphics[{Array[Line[{{-10 + Sin[#], #}, {10 + Sin[#], #}}] &, {14}], 
         Red, c /. Interval[{x_, y_}] -> Line@{{x, 0}, {y, 0}}}]

Mathematica graphics

answered Dec 01 '13 at 17:59

Dr. belisarius

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score 1 · Answer 3 · answered Dec 01 '13 at 18:16

1

We can use properties of Interval earlier:

f = Sin[#] + Interval[{-10, 10}]&;
IntervalIntersection @@ Array[f, 14] // N

Interval[{-9.00939, 9.00001}]

answered Dec 01 '13 at 18:16

Kuba

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score 0 · Answer 4 · answered Dec 01 '13 at 20:17

You can answer this question without knowing anything about interval functions: the intersection of all the intervals is the interval between (10-largest value of Sin) and (10+smallest value of Sin). With Sin assuming integer values between 1 and 14, this is:

{10 - Max[Sin[Range[14]]], 10 + Min[Sin[Range[14]]]}
{10 - Sin[14], 10 + Sin[11]}//N
{9.00939, 9.00001}

how do I can create a list of the first interval such as [-10+Sin [k], 10+Sin [K]]

4 Answers4