Question

Помогите с решением добрые люди

Answer 1

$arccos(sin4)=?\\sin4approx sin229,2^circ in 3; chetverti; ; Rightarrow ;; sin4=sin(pi +(4-pi ))=-sin(4-pi )\\sin(4-pi )=cosBig (frac{pi}{2}-(4-pi )Big )\\arccos(sin4)=arccosBig (-sin(4-pi )Big )=pi -arccosBig (sin(4-pi )Big )=\\=pi -arccosBig (cos(frac{pi}{2}-(4-pi))Big )=pi -Big (frac{pi }{2}-(4-pi )Big )=pi -(frac{3pi}{2}-4)=\\=4-frac{pi}{2}$

$ili\\quad arccos(sin4)=arccos(cosunderbrace {(frac{pi}{2}-4)}_{in 3 chetvert})=arccos(cosunderbrace {(4-frac{pi}{2})}_{in 2 chetvert})=4-frac{pi}{2}\\\star ; ; arccos(cosa)=a; ,; esli; ; 0leq aleq pi ; ; star$