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# Why do we use the chain rule for trigonomtric functions? watch

1. I thought you should use the product rule cos you're multiplying them
i.e sin(2x+2) sin x (2x+2) .
I sin(2x+2) sin x (2x+2) .
Nope.
3. It's a function though, not an actual "thing", f(x) does not refer to f times x, it just represents a function of x. Product rule is if you are differentiating two functions multiplied together, such as sin(2x+2)cos(x). So you can't just replace sin(x) by sin times x, as sin represents a function rather than some algebraic expression.
4. sin on its own does not mean anything. You have to have some value or variable in the function itself.
5. (Original post by B_9710)
sin on its own does not mean anything. You have to have some value or variable in the function itself.
(Original post by JN17)
It's a function though, not an actual "thing", f(x) does not refer to f times x, it just represents a function of x. Product rule is if you are differentiating two functions multiplied together, such as sin(2x+2)cos(x). So you can't just replace sin(x) by sin times x, as sin represents a function rather than some algebraic expression.
(Original post by JLegion)
Nope.
I see!! Thank you!!

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