JEE Main 2019 Mathematics question
If ; α, β ∈ [0, π], then cos(α + β) − cos(α − β) is equal to:
Answer: (A)
Solution
AM ≥ GM on forces sin α = 1, cos β = 1/√2; value = −2 sin α sin β = −√2.
If ; α, β ∈ [0, π], then cos(α + β) − cos(α − β) is equal to:
AM ≥ GM on forces sin α = 1, cos β = 1/√2; value = −2 sin α sin β = −√2.