Online Algebra Calculator
Many of users do not use powerful Maxima computer algebra system for systematic work, but for ad hoc algebraic calculations – equations, functions, matrixes, etc. only. To do this job, it is not useful to download the whole application from a web site.
Function: fourth (<expr>) Returns the 4th item of expression or list <expr>. See first for more details.
![Fourth Example a : 0;
b : 1;
sol : first(solve ([a*x_p + b*y_p + c = 0, a*x_q + b*y_q + c = 0, a*x_r + b*y_r + c = 0, x_1*y_p + (0 - x_p)*y_1 = t_1*y_p, x_1*y_q + (t_2 - x_q)*y_1 = t_2*y_q, x_1*y_r + (t_3 - x_r)*y_1 = t_3*y_r],[x_p,y_p,x_q,y_q,x_r,y_r]));
sol2 : solve(at ([x_2*y_p + (t_1pr - x_p)*y_2 = t_1pr*y_p,x_2*y_q + (t_2pr - x_q)*y_2 = t_2pr*y_q,x_2*y_r + (t_3pr - x_r)*y_2 = t_3pr*y_r], sol),[x_1,y_1,x_2,y_2,c]), ratsimp;
tex(fourth(sol2));](http://maxima-online.org//plot.html?g=i-345995133.png&t=img&db=r-1271893189)
(%o1) true (%i2)