So why not use subs? It works fine, as long as you use it as designed.
syms x
a = 5;
y = a*sin(x)^2 /(sin(x) + cos(x))
y =
(5*sin(x)^2)/(cos(x) + sin(x))
subs(y,x,1:pi/10:pi)
ans =
[ (5*sin(1)^2)/(cos(1) + sin(1)), (5*sin(739805897222023/562949953421312)^2)/(cos(739805897222023/562949953421312) + sin(739805897222023/562949953421312)), (5*sin(458330920511367/281474976710656)^2)/(cos(458330920511367/281474976710656) + sin(458330920511367/281474976710656)), (5*sin(1093517784823445/562949953421312)^2)/(cos(1093517784823445/562949953421312) + sin(1093517784823445/562949953421312)), (5*sin(317593432156039/140737488355328)^2)/(cos(317593432156039/140737488355328) + sin(317593432156039/140737488355328)), (5*sin(1447229672424867/562949953421312)^2)/(cos(1447229672424867/562949953421312) + sin(1447229672424867/562949953421312)), (5*sin(812042808112789/281474976710656)^2)/(cos(812042808112789/281474976710656) + sin(812042808112789/281474976710656))]
Not very easy to read that way, or that useful, so use vpa to improve things a bit...
vpa(subs(y,x,1:pi/10:pi))
ans =
[ 2.5621910014165363100864295707477, 3.8309204938871849945381706934322, 5.2967473394750604192098370433573, 7.6345151542111843907753899746208, 21.303646775422896588787558509401, -4.8465627759522670140582286462245, -0.45155218609854555823864593466888]
Best Answer