Tentukan nilai dari bentuk cos([tex] \frac{2}{3}[/tex][tex] \pi [/tex]) +sin (-[tex] \frac{7}{6} [/tex][tex] \pi [/tex])+sin([tex] \frac{7}{4} [/tex][tex] \pi

=·[tex]cos 120 degrees + sin - 210 degrees + sin 315 degrees[/tex]
= - 1/2 + 1/2 + (-1/2√2)
= -1/2√2 ≈ - 0.707106781187

[cos(2/3π) + sin(-7/6π) + sin(7/4π)] / cotan(π/4)
= [cos(120) + sin(-210) + sin(315)] / cotan(45)
= [(-1/2) * 1/2 * (-1/2 √2)] / 1
= (-1/2) * 1/2 * (-1/2 √2)
= -1/4 * (-1/2 √2)
= 1/8 √2