Nilai 2sin π/2 – 2sin 7π/6 + 4sin 5π/4​

π =180°

Nilai 2sin π/2 – 2sin 7π/6 + 4sin 5π/4​

= 2 sin 90 – 2 sin 210 + 4 sin 225

= 2 sin 90 – 2 sin (180 + 30) + 4 sin (180+45)

= 2 (sin 90) – 2 (- sin 30) + 4 ( – sin 45)

= 2 ( 1 )  + 2  (1/2 )  + 4  ( – 1/2 √2)

=  2 + 1 – 2√2

= 3 – 2√2