Question

$\sin( - 17\pi \div 4)$
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Answer 1

Sin (- 17 *π/4)

sin(- 17*180/4)

- sin(17 *45)

-sin(720+45)

-sin45

-1/sqrt2

since sin(720+ 45) means 45° liye in 1 st quedrent so sign is +ve and the 720 is 4 multiple of 180° which is even so identity is not changed .