2/pi*x\
cos |----|
\14/5/
cos((pi*x)/(14/5))^2
Let .
Apply the power rule: goes to
Then, apply the chain rule. Multiply by :
Let .
The derivative of cosine is negative sine:
Then, apply the chain rule. Multiply by :
The derivative of a constant times a function is the constant times the derivative of the function.
The derivative of a constant times a function is the constant times the derivative of the function.
Apply the power rule: goes to
So, the result is:
So, the result is:
The result of the chain rule is:
The result of the chain rule is:
Now simplify:
The answer is:
/pi*x\ /pi*x\
-5*pi*cos|----|*sin|----|
\14/5/ \14/5/
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7
2 / 2/5*pi*x\ 2/5*pi*x\\
25*pi *|sin |------| - cos |------||
\ \ 14 / \ 14 //
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98