Math, asked by achieveit, 1 year ago

sin (5pi over 4) minus Cos (3 pi over 4)​

Answers

Answered by ihrishi
1

Answer:

sin( \frac{5 \pi}{4} ) - cos( \frac{3 \pi}{4} ) \\  = sin( \pi + \frac{\pi}{4} ) - cos( \pi - \frac{\pi}{4} )  \\  =  \{ - sin(\frac{\pi}{4} ) \} -  \{ -  cos(\frac{\pi}{4} )\} \\  = - sin(\frac{\pi}{4} ) + cos(\frac{\pi}{4} ) \\  =  -  \frac{1}{ \sqrt{2} }  + \frac{1}{ \sqrt{2} } \\  = 0 \\  \\ reasons:  \\ (i) \: sin( \pi + \theta) =  - sin(\theta) \\ (ii) \: cos( \pi  -  \theta) =  - cos(\theta)

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