Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: Finding zeros
Replies: 1   Last Post: Sep 26, 2010 11:06 PM

 Messages: [ Previous | Next ]
 gautamsethi@gmail.com Posts: 27 Registered: 10/20/05
Finding zeros
Posted: Sep 26, 2010 9:13 PM

Hi all:
I'm trying to figure out a solution to the following problem. I have
the vectors x and y:

x y

0.0000 0.0000
0.2929 -28.7071
0.5859 -28.4141
0.8788 -28.1212
1.1717 -27.1605
1.4646 -26.8676
1.7576 -26.5746
2.0505 -26.2817
2.3434 -25.9888
2.6364 -25.6959
2.9293 -25.4029
3.2222 -25.1100
3.5152 -24.8171
3.8081 -24.5241
4.1010 -24.2312
4.3939 -23.9383
4.6869 -23.6453
4.9798 -23.3524
5.2727 -23.0595
5.5657 -22.7666
5.8586 -22.4736
6.1515 -22.1807
6.4444 -21.8878
6.7374 -21.5948
7.0303 -21.3019
7.3232 -21.0090
7.6162 -20.7161
7.9091 -20.4231
8.2020 -20.1302
8.4949 -19.8373
8.7879 -19.5443
9.0808 -19.2514
9.3737 -18.9585
9.6667 -18.6655
9.9596 -18.3726
10.2525 -18.0797
10.5455 -17.7868
10.8384 -17.4938
11.1313 -17.2009
11.4242 -16.9080
11.7172 -16.6150
12.0101 -16.3221
12.3030 -16.0292
12.5960 -15.7363
12.8889 -15.4433
13.1818 -15.1504
13.4747 -14.8575
13.7677 -14.5645
14.0606 -14.2716
14.3535 -13.9787
14.6465 -13.6858
14.9394 -13.3928
15.2323 -13.0999
15.5253 -12.8070
15.8182 -12.5140
16.1111 -12.2211
16.4040 -11.9282
16.6970 -11.6352
16.9899 -11.3423
17.2828 -11.0494
17.5758 -10.7565
17.8687 -10.4635
18.1616 -10.1706
18.4545 -9.8777
18.7475 -9.5847
19.0404 -9.2918
19.3333 -8.9989
19.6263 -8.7060
19.9192 -8.4130
20.2121 -8.1201
20.5051 -7.8272
20.7980 -7.5342
21.0909 -7.2413
21.3838 -6.9484
21.6768 -6.6554
21.9697 -6.3625
22.2626 -6.0696
22.5556 -5.7767
22.8485 -5.4837
23.1414 -5.1908
23.4343 -4.8979
23.7273 -4.6049
24.0202 -4.3120
24.3131 -4.0191
24.6061 -3.7262
24.8990 -3.4332
25.1919 -3.1403
25.4848 -2.8474
25.7778 -2.5544
26.0707 -2.2615
26.3636 -1.9686
26.6566 -1.6756
26.9495 -1.3827
27.2424 -1.0898
27.5354 -0.7969
27.8283 -0.5039
28.1212 -0.2110
28.4141 0.0819
28.7071 0.3749
29.0000 0.6678

and i want to calculate the value of x closest to the largest non-
trivial zero of y. In this case, that would be x = 28.4141. In the
above case, there are only two zeros of y (including the trivial one)
but I might have other functions in which there may multiple non-
trivial zeros and I would want the code to pick the value of x closest
to the largest one. If there are no non-trivial zeros, then the code
should pick the trivial solution. Any pointers will be appreciated.

Gautam.

Date Subject Author
9/26/10 gautamsethi@gmail.com
9/26/10 Walter Roberson