2016-12-06 13:41:33 +0200 received badge ● Student (source) 2016-11-24 22:44:25 +0200 commented question Solving large trigonometric fucntions @slelievre thanks and done 2016-11-24 22:43:34 +0200 commented question Solving large trigonometric fucntions @tmonteil I was expecting a set of 4 solutions over the interval of 0 to 2*pi for phi. I solved this problem earlier on Wolframalpha before I added the terms sigma_a1 and sigma_a2 to my equations and got the following for one solution (note that variable names are different but the problem was essentially the same) t = -cos^(-1)((-sqrt((2 F X Y^2 Z cos(2 a) - 2 F X Y^2 Z)^2 - 4 (-4 F^2 X Y cos(a) + 2 F^2 X^2 + 2 F^2 Y^2) (4 F^2 X Y cos(a) - F^2 Y^2 cos(2 a) - X^2 Y^2 Z^2 cos(2 a) - 2 F^2 X^2 - F^2 Y^2 + X^2 Y^2 Z^2)) - 2 F X Y^2 Z cos(2 a) + 2 F X Y^2 Z)/(2 (-4 ... 2016-11-24 22:36:20 +0200 received badge ● Editor (source) 2016-11-24 02:03:19 +0200 asked a question Solving large trigonometric fucntions Hi everyone, I'm new to sage and would like to use it to give me an exact solution to the derivative of a large trig function. I have been tinkering around with the different trig simplification routines to no avail. Here is the current incarnation of my code: var("theta phi r I sigma_a1 sigma_a2 M_1 M_2 F_tu") import sympy as sy M1(phi)=M_1*cos(phi+pi/2) M1=M1.trig_reduce() M2(phi)=M_2*cos(phi+theta+pi/2) M2=M2.trig_reduce() sigma_b1(r,phi)=M1(phi - pi/2)*r/I+sigma_a1 sigma_b1=sigma_b1.trig_reduce() sigma_b2(r,phi)=M2(phi - pi/2)*r/I+sigma_a2 sigma_b2=sigma_b2.trig_reduce() sigma_alt(r,phi)=sigma_b1-sigma_b2 sigma_alt=sigma_alt.trig_reduce() sigma_mean(r,phi)=(sigma_b1-sigma_b2)/2 sigma_mean=sigma_mean.trig_reduce() sigma_alteq(r,phi)=F_tu*sigma_alt/(F_tu-sigma_mean) sigma_alteq=sigma_alteq.trig_reduce() sol=diff(sigma_alteq,phi) sol_reduc=SR(sy.fu(sy.sympify(sol))); sol_reduc show(sol_reduc) solve(sol_reduc,phi)  Sorry, I do not know how to make the code appear in a window. The final result it gives me is: [sin(phi + theta) == M_1*sin(phi)/M_2] Can someone please help me or at least point me in the right direction. Thanks.