sin((-7pi)/12)
2007-10-09 06:59:08 · 5 answers · asked by tweek_2_4 2 in Science & Mathematics ➔ Mathematics
Note first that -7pi/12 = -pi/2 - pi/12
Use the identity sin(a - b) = sin(a)cos(b) - cos(a)sin(b):
sin(-7pi/12) = sin (-pi/2)*cos(pi/12) - cos(-pi/2)*sin(pi/12) = (-1)*cos(pi/12) - (0)*sin(pi/12) = -cos(pi/12)
Now use the half-angle identity for cos(x/2).
You should get sin(-7pi/12) = -sqrt[2 + sqrt(3)]/2
2007-10-09 07:25:58 · answer #1 · answered by Anonymous · 0⤊ 0⤋
=-sin(7pi/12) =-sin( pi/4+pi/3)= -(1/2sqrt2*1/2+1/2sqrt(2)*1/2sqrt(3) ) =-(1/4*sqrt(2) *(1+sqrt(3))
2007-10-09 07:23:37 · answer #2 · answered by santmann2002 7 · 0⤊ 0⤋
the exact answer would be [(-sqrt(3)-1)*sqrt(2)]/4
2007-10-09 07:18:55 · answer #3 · answered by shadoyaj 4 · 0⤊ 0⤋
exact answer is with no decimals and the answer is 0
2007-10-09 07:16:10 · answer #4 · answered by programhelp 2 · 0⤊ 0⤋
-.9659258263
2007-10-09 07:02:37 · answer #5 · answered by kyle f 2 · 0⤊ 0⤋