Question

The value of ${\cos }^2{73}^{\circ }+{\cos }^2{47}^{\circ }-\sin {43}^{\circ }+{\sin }^2{107}^{\circ }$ is equal to :

• A. $1$
• B. 0.783
• C. 0
• D. ${\sin }^2{73}^{\circ }+{\cos }^2{73}^{\circ }$

Answer 1

The correct option is A $1$

Given

${\cos }^2{73}^{\circ }+{\cos }^2{47}^{\circ }-{\sin }^2{43}^{\circ }+{\sin }^2{107}^{\circ }$

${\cos }^2{73}^{\circ }+{\cos }^2{47}^{\circ }-{\cos }^2{47}^{\circ }+{\sin }^2{107}^{\circ }$

${\cos }^2{73}^{\circ }+{\sin }^2{107}^{\circ }$

${\cos }^2{73}^{\circ }+{\sin }^2(180-73{)}^{\circ }$

${\cos }^{2}73+{\sin }^{2}73=1$