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 .