Can I get an explanation please? Thanks!
derivative of tan2x = cos3y

Question

Can I get an explanation please? Thanks! 
derivative of tan2x = cos3y

anonymous · Answer

When finding the derivative of a trig function, why do you take the derivative of the inside as well?

anonymous · Answer

O no its saifoo.khan lol

anonymous · Answer

Aww how sweet lol

.sam. · Answer

you take the derivative of the inside because you're using chain rule

anonymous · Answer

But it isnt to a power, can you explain the chain rule/

.sam. · Answer

anonymous · Answer

The problem is why dont you do the chain rule with cos3y? 
I thought it was -sin3y x 3 but theres no 3...

.sam. · Answer

the answer is 
-3sin3y

.sam. · Answer

you have already done the chain rule  -sin3y x 3  the 3 go in front of the -sin3y x 3
-3sin3y

anonymous · Answer

the answer says that it is not -3sin3y just -sin3y

.sam. · Answer

what's with the tan2x in your first post?

.sam. · Answer

the answer cannot be just -sin3y

anonymous · Answer

you are right. textbook must be wrong. Thanks