TEXAS INSTRUMENTS 11. antuo of \( \sin \left(-\frac{4 \pi}{3}\right. \) radians \( ) \) b. \( \sqrt{3} \) vahuc of \( \cos \left(-\frac{7 \pi}{4}\right. \) raduans \( ) \) b. \( \frac{1}{2} \) c. ve, negative. or zero? tegative

Step 1 ：\( \sin \left(-\frac{4 \pi}{3}\right) = \sin \left(\frac{2 \pi}{3}\right) \)

Step 2 ：\( \sin \left(\frac{2 \pi}{3}\right) = \frac{\sqrt{3}}{2} \)

Step 3 ：\( \cos \left(-\frac{7 \pi}{4}\right) = \cos \left(\frac{\pi}{4}\right) \)

Step 4 ：\( \cos \left(\frac{\pi}{4}\right) = \frac{1}{\sqrt{2}} \)