Tentukan nilai dari sin 240°+sin225°+cos315°

Sin 240° = sin(270°-30)
= -cos30°
= -1/2 √3
sin 225° = sin(180+45)
= -sin 45°
=-1/2 √2
cos315° = cos(270+45)
= sin 45°
=1/2√2

-1/2 √3 - 1/2 √2 + 1/2 √2 = - 1/2 √3

[tex] \sin(240) + \sin(225) + \cos(315)
= ( - \frac{1}{2} \sqrt{3} ) + ( - \frac{1}{2} \sqrt{2} )+ ( \frac{1}{2} \sqrt{2} ) \\ = - \frac{1}{2} \sqrt{3} [/tex]
jawabannya
[tex] - \frac{1}{2} \sqrt{3} [/tex]
semoga membantu :)