(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

I'm learning now about darivative all by my self (without a teacher) and I'm not sure about this development

2. Relevant equations

3. The attempt at a solution

[tex]Y=senx[/tex]

[tex]y+{\Delta}Y=sen(x+{\Delta}Y)[/tex]

[tex]{\Delta}Y=senx*cos{\Delta}x+ sen{\Delta}x*cosx[/tex]

What about this cos,what is it doing in the equation?

I really don't get it.

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# Homework Help: Derivatives of trigonometric functions

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