Question

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

• A. 1/2
• B. 3/4
• C. 1
• D. None of these

Answer 1

The correct option is A 1/2

$={\cos }^2{73}^0+{\cos }^2{47}^0-{\sin }^2{43}^0+{\sin }^2{107}^0$

$={\cos }^2(180-107)+{\sin }^2{43}^0-{\sin }^2{43}^0+{\sin }^2{107}^0$

$={\cos }^2{107}^0+{\sin }^2{107}^0$

$=1$

Hence, this is the answer.