Question

If $\alpha ={\left({\cos }^{-1}x\right)}^2+{\left({\cos }^{-1}y\right)}^2$ and $\beta =\left|{\sin }^{-1}z\right|+\left|{\cos }^{-1}w\right|$ are such that $\alpha \beta =0$ and $l=x+y+z+w$, then

• A. maximum value of $l$ is 3 .
• B. minimum value of $l$ is -1 .
• C. minimum value of $l$ is -2 .
• D. maximum value of $l$ is 4 .

Answer 1

Answer: (B), (D)

Correct answer is (b) minimum value of $l$ is -1 . Correct answer is (d) maximum value of $l$ is 4 .