Question

Total number of values of 'x' where the function

f(x) = cosx + cos$\sqrt{2}$xattains it's maximum value is/are

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

Answer 1

Answer: (A)

1

Answer 2

Maximum value of f(x) = cosx + $\cos \sqrt { 2 } x$ is clearly equal to two and it occurs when

cosx = 1, $\cos \sqrt { 2 } x$ = 1, i.e. x = 2n, π, = 2n₂π, where n₁ and n₂ are integers.

⇒ x = 0 is the only possibility.