How to differentiate sin2x??

Thats not my real question... i only asked that cos everyone seems to only be going to the threads that have an easy title. My previous thread was multiple integrals, which no one has even looked at. So now that youre here, you may as well have a go at this:

The density per unit area of a circular lamina of radius a varies as the cube of the distance from a single point on the edge. Find the mass of this lamina.

im guessing id have to do ρdxdydz, and maybe use polar coordinates but im still kind of stuck.

Any help would be much appreciated

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Reply 1

Glutamic Acid

Use the chain rule, and you get 2cos(2x). Oh wait, that doesn't help with your problem at all. See the flaw in your master plan?

Reply 2

RTARD

My 'master' plan as you call it actually worked. My main question was indeed how to differentiate sin2x, however i knew if i had just asked it straight away, i would have got some response which would not have been the actual answer, but rather some little (useless) tip on how to get the answer. But then i thought... why not devise this 'master' plan and get some guy that is easy to deceive to give me the answer straight away. Im glad i found that guy.
So do i see the flaw in this master of a plan?... No, all i see is success, sweet success.

Reply 3

Glutamic Acid

Oh, excellent. In which case, it'd be of no loss if no one were to provide help with your second question. :smile:

Reply 4

electriic_ink

tl;dr. I'll just answer the question in the title.

Ans: 2 cos 2x by using the chain rule with f(x) = 2x (therefore f'(x)=2). If y=sin f(x) then

\frac{dy}{dx}

=f'(x)cosf(x)

Reply 5

RTARD

Exactly my friend, exactly. That question was made up, i guess its that that moved it from being just a plain old plan to a 'master' plan, as you described it.

Reply 6

RTARD

electriic_ink

tl;dr. I'll just answer the question in the title.

Ans: 2 cos 2x by using the chain rule with f(x) = 2x (therefore f'(x)=2). If y=sin f(x) then

\frac{dy}{dx}

=f'(x)cosf(x)

Wow, youve been (deceived)^2. Even after seeing everything ive written, youre still answering the question! I think this plan just turned from being a master plan to a MEGAmaster plan

Reply 7

electriic_ink

RTARD

Wow, youve been (deceived)^2. Even after seeing everything ive written, youre still answering the question! I think this plan just turned from being a master plan to a MEGAmaster plan

I'm glad I could help you.

Reply 8

RTARD

umm... ok... i think you need to do what i did, except use the question 'definition of fail' in the english help forum. Dont worry, i havnt copyrighted this MEGAmaster plan yet, although i do plan on doing so, so if i were you i would get on with it quickly! If you need help just ask, dont be shy. But when you ask for help, make sure you use the MEGAmaster plan, otherwise i will be forced to answer your question by just offering some (useless) tips.

Reply 9

Captain Biggles

I would say more a specific maths fail?

Reply 10

RTARD

Captain Biggles

I would say more a specific maths fail?

Aww, somebody wants some attention! Dont worry, here i am... attention attention!

happy!

Reply 11

Captain Biggles

RTARD

Aww, somebody wants some attention! Dont worry, here i am... attention attention!

happy!

Uhuh.

Reply 12

electriic_ink

RTARD

Aww, somebody wants some attention! Dont worry, here i am... attention attention!

happy!

Can I have some attention? :frown:

Reply 13

RTARD

Youre not be able to accept having been deceived. The first sign of someone having been deceived is them not accepting it. Just accept it my friend, and then you will be able to move on, otherwise this will keep bugging you. Trust me, i know.

Reply 14

RTARD

electriic_ink

Can I have some attention? :frown:

Sure you can! After all, i have you to thank for making this minor 'master' plan into the MEGAmaster plan it is today! so here you go.. attention attention!

Reply 15

RTARD

Yet here you are.. back again.. (my micromaster plan worked! :biggrin:

)

Reply 16

electriic_ink

RTARD

Sure you can! After all, i have you to thank for making this minor 'master' plan into the MEGAmaster plan it is today! so here you go.. attention attention!