Trig
posted by Carol .
Could someone please show me how
1 / ( 4 tan (x/2) + 2 )
is converted to:
( sin (x/2) /( 2 sin (x/2) + cos (x/2))
TIA
Carol

lets check it at x=0, and x=PI/2
x=0: 1/4(1+2)=1/12
(sin45/(2sin45+cos45)=.707/(1.414+.707) does not equal 1/12 
that was at x=90 deg, the identity did not hold. Now at x=0
1/4(0+2)=1/8
0/(0+.7) does not equal 1/8