what's he problem. Got no calculator?
sin 2pi/7 = .7818
cos 3pi/14 = .7818
so, 2/3
Note that 2pi/7 + 3pi/14 = pi/2
simplify: (2sin(2pie/7))/(3cos(3pie/14)
2 answers
recall that sinA = cos(π/2 -A)
(2sin(2pie/7))/(3cos(3pie/14)
= 2cos(π/2 - 2π/7) / 3cox(3π/14)
= 2cos(3π/14) / 3cos(3π/14)
= 2/3
(2sin(2pie/7))/(3cos(3pie/14)
= 2cos(π/2 - 2π/7) / 3cox(3π/14)
= 2cos(3π/14) / 3cos(3π/14)
= 2/3