1) Tentukan nilai dari sin 240° + sin 225° + cos 315° 2) Tentukan nilai dari cos 150° + sin 45° + 1/2 cot 330°

nomor 1.
[tex] \sin( {240}^{o} ) + \sin( {225}^{o} ) + \cos( {315}^{o} ) \\ = ( - \frac{1}{2} \sqrt{3} ) - ( - \frac{1}{2} \sqrt{2} ) + \frac{1}{2} \sqrt{2} \\ = \sqrt{2} - \frac{1}{2} \sqrt{3} [/tex]
nomor 2.
[tex] \cos( {150}^{o} ) + \sin( {45}^{o} ) + \frac{1}{2} \cot( {330}^{o} ) \\ = \cos( {150}^{o} ) + \sin( {45}^{o} ) + \frac{1}{2} \frac{1}{ \tan( {330}^{o} ) } \\ = ( - \frac{1}{2} \sqrt{3} ) + \frac{1}{2} \sqrt{2} + \frac{1}{2} \frac{1}{ - \sqrt{3} } \\ = \frac{1}{2} \sqrt{2} - \frac{1}{2} \sqrt{3} + \frac{1}{ - 2 \sqrt{3} } \\ = \frac{1}{2} \sqrt{2} - \frac{1}{2} \sqrt{3} + ( \frac{ - 2 \sqrt{3} }{4 \times 3} ) \\ = \frac{1}{2} \sqrt{2} - \frac{1}{2} \sqrt{3} - \frac{1}{6} \sqrt{3} \\ = \frac{1}{2} \sqrt{2} - \frac{2}{3} \sqrt{3} [/tex]
semoga bermanfaat,,