Question

can someone explain steps to get from
sinL(1 + cosB)
to
4sinL/2 cos L/2 cos^2 B/2

Answer 1

sinl=2sin(l/2)cos(l/2)
and cosb=(2cos^2(b/2)-1)

so

sinl(1+cosb)
=
2sin(l/2)cos(l/2)(1+2cos^(b/2)-1)
=
2sin(l/2)cos(l/2)(2cos^2(b/2))
=
4sin(l/2)cos(l/2)cos^2(b/2)

Answer 2

Thanks :)

Answer 3

welcome..

Answer 4

can you explain me how did you get
cosb = cos^2b -1