Question

Differentiate f(x) = 2 sin x - cos 2x?

Why is the solution: f'(x) = 2 cos x + 2 sin 2x?
Where does the 2 in front of sin 2x come from?...

The answer is from the book, by the way.

Answer 1

derivative rules

Answer 2

and product rule as well

Answer 3

it comes from applying the chain rule substitution u=2x to the -cos (2x)
not product rule

Answer 4

Oh, product rule

Answer 5

this is how I do it...leave the first term alone deal with the second + leave the second term alone deal with the first...

Answer 6

2 is du/dx

Answer 7

the derivative of a number is always a 0

Answer 8

like f(x)=3 f'(x) = 0

Answer 9

chain rule, not product rule

Answer 10

okay. so letme get this clear..

Answer 11

the question is on the -cos(2x)

Answer 12

f'(x) = - cos 2x = - cos 2x * cos 2?

Answer 13

oh wiat, it should be - cos 2x * 2

Answer 14

because u is 2x... and u' is 2(1) = 2??

Answer 15

chain rule? plzzz