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How do I find the value of sin 225?

1 Answer

Oct 29, 2015

$- \frac{1}{\sqrt{2}}$ $-1/sqrt2$

Explanation:

${sin 225}^{\circ} = sin (180^{\circ} + 45^{\circ})$ $sin225^@=sin(180^@+45^@)$

$= {sin 180}^{\circ} {cos 45}^{\circ} + {cos 180}^{\circ} {sin 45}^{\circ}$ $=sin180^@cos45^@+cos180^@sin45^@$

$= (0) (\frac{1}{\sqrt{2}}) + (- 1) \frac{1}{\sqrt{2}}$ $=(0)(1/sqrt2)+(-1)1/sqrt2$

= $- \frac{1}{\sqrt{2}}$ $-1/sqrt2$

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