Question

Find the derivative of:

Answer 1

\[7\div-3\cos 3x\]

Answer 2

\[\frac{7}{-3\cos{3x}}\]Remember, a constant can always be factored out, or you could use the quotient rule.

Answer 3

When I worked it out, i ended up with an extra number

Answer 4

can we make this sec3x and then diff @rational

Answer 5

\[7\sin3x \div-3\cos^23x\] this is what i got

Answer 6

we havent learnt sec

Answer 7

So... \[\frac{\frac{d}{dx}(7)(-3\cos(3x))-\frac{d}{dx}(-3\cos(3x))(7)}{(-3\cos(3x))^2}\]

Answer 8

If you're just getting used to taking derivatives.

Answer 9

A quick derivation of the derivative of sec x if you want me to explain any part of this more feel free to ask :) \[\large \frac{d}{dx}\sec(x) = \frac{d}{dx} (\cos x )^{-1}=-1(\cos x)^{-2}(-\sin x)=\tan x \sec x\]

Answer 10

I think I figured out what i did wrong. Thanks anyway for the help!!

Answer 11

Which method did you use?

Answer 12

You could also use the product rule which @Kainui hinted at. \[7(-3\cos(3x))^{-1}\]where \(f(x) =7\) and \(g(x) = -3\cos(3x)\)

Answer 13

anyways
u got ur mistake and now its cleared
All the best @adriana_98

Answer 14

Thanks. Exam is tomorrow :(

Answer 15

Good luck. May Newton be with you.

Answer 16

lol

Answer 17

Thanks!! @Jhannybean

Answer 18

No problem :)