Discussion Forum : Application Of Derivatives
Question -
The number of values of x where the function f(x) = 2 (cos 3x + cos √3x attains its maximum, is
Answer: Option A
:
A
We have,
f(x)=2(cos 3x+cos√3x)=4 cos(3+√32)x cos(3−√32)x⩽4
and it is equal to 4 when both cos (3+√32) x and cos(3−√32)
Are equal to 1 for a value of x. This is possible only when x = 0.
Hence (a) is the correct answer.
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:
A
We have,
f(x)=2(cos 3x+cos√3x)=4 cos(3+√32)x cos(3−√32)x⩽4
and it is equal to 4 when both cos (3+√32) x and cos(3−√32)
Are equal to 1 for a value of x. This is possible only when x = 0.
Hence (a) is the correct answer.
Was this answer helpful ?
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