Question

ПОМОГИТе
найдите значение функцим $y= frac{1}{sin^{2}x }$ при:
$x= frac{3 pi }{4}$

Answer 1

$y( frac{3pi}{4} )= frac{1}{sin^2( frac{3pi}{4} )} = frac{1}{[sin( frac{pi}{2}+ frac{pi}{4} )]^2} = frac{1}{[cos(frac{pi}{4} )]^2} = frac{1}{ (frac{ sqrt{2} }{2})^2 } = frac{1}{ frac{1}{2} } =2$