order x
define mhalf = -.5    ;this example should be run with PFSAF.EXE
maxe=30
nbinomial=30
define aa
1
-x^2

compute sb = aa^mhalf
substitute t for x in sb
the derivative of y wrt t is sb
define arcsin = y
taylor order = 31
taylor expand arcsin in t
substitute 0 for y in arcsin
substitute x for t in arcsin
print arcsin

substitute .5 for x in arcsin
define pi = 6.*arcsin
print pi  ;accurate to 10 decimal places
end input