x = 4 z = + x 5 eval z z = * x z eval z x = / z x eval x q = 3.141592653897 r = cos ( q ) s = arc cos ( r ) eval q eval r eval s f = -0.5 g = 10 h = - f g eval h i = + + / g g g f eval i eval kdngdf sine 4 z = / 4 0 x = -3.6 y = 4 var = arc tan ( + x y ) eval var z = 10.08934257789790879732498579438 q = 3 eval z eval q eval var var = + z q eval var var = + - + x y z q eval var var = - 3 4 eval var var = / 3 0 eval var var = rads ( 90 ) eval var var = exp ( 9 2 ) eval var eval varunknown var = + q varunknown eval var