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+--- Thread: Solving equations in a given range (/thread-14705.html)
Solving equations in a given range - Jan 11 - 03-23-2020 05:14 PM
I solve the equation TAN (3x) = - x ^ 2 + 3.
The calculator gives six solutions in the range {-3,633 to 2,695}. OKAY. When we set the range of solutions in the range x = 0 to 10, he will give all the solutions correctly. OKAY. Next, when we set x = 10 to 15, it will give only two solutions. However, there are 4 solutions. Now I set the range x = 25 to 30. HP Prime finds no solution. There are as many as 5 solutions in this range.
I checked how the TI-Nspire CX II-T calculator does it. I do all the examples great, perfectly. See this in the attached screenshots of both calculators.
[attachment=8209][attachment=8210]
RE: Solving equations in a given range - parisse - 03-24-2020 07:00 PM
That's because the default step for the bisection solver is too large to detect the roots. You can obtain more solutions by adding an optional argument, like this
solve(tan(3x)=-x^2+3,x=10..15,xstep=0.001)
or
solve(tan(3x)=-x^2+3,x=25..30,10000)
RE: Solving equations in a given range - Jan 11 - 03-24-2020 07:25 PM
Dear Parisse. Thank you very much for very valuable advice. I've never heard of it. Great, all equations have been solved. Thank you again.
RE: Solving equations in a given range - parisse - 03-24-2020 08:13 PM
I have just increased the default number of steps, this will detect more solutions if the optional argument is not given.