help with differentials?? (easy) formula for dy if y=tanx

[gallentlyspeaking]

need to find the formula for dy if y=tanx and the formula for (delta) y if y=tanx using diffentials


.... aren't these asking for the same thing, or am I missing something?

got tan(x+(delta)x)-tanx for both.. I feel like this is too easy. help?

 

[Steven G]

need to find the formula for dy if y=tanx and the formula for (delta) y if y=tanx using diffentials


.... aren't these asking for the same thing, or am I missing something?

got tan(x+(delta)x)-tanx for both.. I feel like this is too easy. help?

If y = tan(x) then dy = sec²(x) dx and \(\displaystyle \delta\)y = sec²(x) \(\displaystyle \delta\)x. Is that what you are looking for?

 

[pka]

If y = tan(x) then dy = sec²(x) dx and \(\displaystyle \delta\)y = sec²(x) \(\displaystyle \delta\)x. Is that what you are looking for?

Actually that does not help here. In fact, it is what is to proved.
\(\displaystyle \displaystyle{\lim _{h \to 0}}\frac{{\tan (x + h) - \tan (x)}}{h} = ?\)