The function is .
Apply derivative with respect to .
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The function is .
The function is not defined for the odd multiples of
.
The Domain of the function is .
Hence the one of the largest interval is .
Write the derivative as a function of .
.
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Trigonometric identities : .
Substitiute in the function
.
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Substitute in the function
.
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The derivative of is
.
The one of the largest interval is .
The derivative of in terms of
is
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