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seen Apr 19 at 13:59

Mar
22
comment Intersection of any triangle with a circle in Cartesian coordinates
Yes, I start with 3 points for the triangle , 1 point for the centre of the circle, length of its radius. I could not find a way to write a single Solve between the equation of the circle and an analytic expression representing the triangle. Precision of the intersection points coordinates is very important.
Mar
22
revised Intersection of any triangle with a circle in Cartesian coordinates
rewording of the first paragraph, to make clearer what my question is about
Mar
22
comment Intersection of any triangle with a circle in Cartesian coordinates
The question is about getting the cartesian coordinates of the points where a circle intersects a triangle - with less code as here where I had to plot three lines and solve three equations, where each line intersects the circle.
Mar
21
asked Intersection of any triangle with a circle in Cartesian coordinates
Mar
2
accepted Implementing nested subtotals
Mar
2
comment Implementing nested subtotals
thanks for your extended and adaptive answer which made discover the usefulness of FlipView. I thought about partly emulating the Excel pivot tables but it is a question too presumptuous to ask by a modest MMA user as myself who may not thoroughly understand any answer received.
Feb
28
asked Implementing nested subtotals
Jan
19
comment Solving a polynomial equation with a condition of equality on roots
Indeed! Easier with MMA than with algebra demonstrations! Thanks
Jan
18
comment Solving a polynomial equation with a condition of equality on roots
I'm impressed. How did you find out the relations r1*r2 + r1*r3 + r2*r3 == q, r1*r2*r3 == r - It's not a MMA question but an algebra question.
Jan
18
comment Solving a polynomial equation with a condition of equality on roots
Try Solve[(x^3 - p x^2 + q x - r /. {p -> 41/5, q -> 429/20, r -> -2178/125}) == 0, x] (* your solution *) Solve[(x^3 - p x^2 + q x - r /. {p -> 41/5, q -> 429/20, r -> 2178/125}) == 0, x] (* r sign changed*) Updated prompted by @DanielLichtBlau answer.
Jan
18
comment Solving a polynomial equation with a condition of equality on roots
I like your answer as it is easy with it to find n different instances just by adding ,n at the end of your FindInstance. Is it possible to get an instance by replacing any of the p,q,r parametres by a numerical value? I tried FindInstance[ p == b + 2 a && q == a^2 + 2 a b && r == -a^2 b, {a, b, p, q, r}, Reals] /. {p -> 5} but this does not work
Jan
18
comment Solving a polynomial equation with a condition of equality on roots
xd in your solution is the simple root, xs the double root
Jan
18
accepted Solving a polynomial equation with a condition of equality on roots
Jan
18
comment Solving a polynomial equation with a condition of equality on roots
Ingenious! I wonder why MMA in the ConditionalExpression list xd is always expressed as xd == p - 2 xs (which is correct) and not an expression involving only p,q,r (root3 in my question)
Jan
18
comment Solving a polynomial equation with a condition of equality on roots
I want an expression for r1 and r2 which involves only p, q, r. You suggest an expression for p, q, r which involves r1 and r2. That's different.
Jan
17
asked Solving a polynomial equation with a condition of equality on roots
Jan
13
comment Possibility of evaluating the expression within a NestList at each iteration?
Thanks.Clever use of Rest and Scale was up to your answer unknown to me.
Jan
13
accepted Possibility of evaluating the expression within a NestList at each iteration?
Jan
12
asked Possibility of evaluating the expression within a NestList at each iteration?
Nov
29
comment How can I extract when a select condition is met in a do loop the value of the iterator?
@Gabriel A solution was found by Kevin without using Reap and Sow that I do not know how to use here.The Select has to be of the form [list,crit, 1] because I need to get only the first element of the list that satisfies the criteria.