BMJ

09-30-2002, 10:33 AM

Er... verify something for me guys; Is the derivative of

sin(cos(x))equal to

-cos(cos(x))sin(x):confused:

sin(cos(x))equal to

-cos(cos(x))sin(x):confused:

View Full Version : Math question

BMJ

09-30-2002, 10:33 AM

Er... verify something for me guys; Is the derivative of

sin(cos(x))equal to

-cos(cos(x))sin(x):confused:

sin(cos(x))equal to

-cos(cos(x))sin(x):confused:

Govtcheez

09-30-2002, 10:36 AM

That's not what I got - I got

sin(-sin(x)) * cos(cos(x))

I could be wrong, though.

sin(-sin(x)) * cos(cos(x))

I could be wrong, though.

BMJ

09-30-2002, 10:44 AM

Where did that extra sine come from?

Govtcheez

09-30-2002, 10:45 AM

Chain rule.

BMJ

09-30-2002, 10:49 AM

f(x) = sin(cos(x))

f'(x) = cos(cos(x)) * (-sin(x)) * (1)Right?

f'(x) = cos(cos(x)) * (-sin(x)) * (1)Right?

Govtcheez

09-30-2002, 10:51 AM

Um... Maybe. Like I said, I could be (and likely am) wrong...

Heh, 3 years of calc, and I can't remember a damn thing. Thank you, beer!

Heh, 3 years of calc, and I can't remember a damn thing. Thank you, beer!

Govtcheez

09-30-2002, 10:54 AM

The answer I got from people that are better at this than me was -sin(x) * cos(cos(x)), so the same thing that you got.

Guess it's time to dig out that calc book again.

Guess it's time to dig out that calc book again.

BMJ

09-30-2002, 10:55 AM

I just want to make sure I am remembering this stuff right so that I don't mess my entire week up as I go back trying to figure out what's wrong only to find it's this stuff :rolleyes:

BMJ

09-30-2002, 10:56 AM

Ok thanks Govtcheez! :)

ober

09-30-2002, 11:06 AM

working on... finding... Maple...

ok... I can't locate a free download of it anymore, but it's useful for checking your derivatives/integrals... sorry... you could look around for a copy of it tho.

ok... I can't locate a free download of it anymore, but it's useful for checking your derivatives/integrals... sorry... you could look around for a copy of it tho.

BMJ

09-30-2002, 11:18 AM

I've never heard of it... does it work well?

Govtcheez

09-30-2002, 11:18 AM

ONce you figure it out, it's helpful. I never got the hang of it, though.

BMJ

09-30-2002, 11:20 AM

Hmmm... maybe I should write something to calculate derivative expressions like a TI-89 or Maple does :)

ober

09-30-2002, 11:37 AM

yeah, there's definately a learning curve, but when you can type in an equation and it spits out what you want.... you just can't beat it.

dbaryl

09-30-2002, 11:37 AM

um... what about my TI-92?

BMJ

09-30-2002, 11:45 AM

Ok, then tell me mister TI-92... can you tell if the derivative expression for

y = sin(x^(1/2))+(sin(x)^(-1/2))is

[cos(x^(1/2))]/[2x^(1/2)] + 1/[2(sin(x)^(1/2))]:confused:

y = sin(x^(1/2))+(sin(x)^(-1/2))is

[cos(x^(1/2))]/[2x^(1/2)] + 1/[2(sin(x)^(1/2))]:confused:

ober

09-30-2002, 12:24 PM

don't test the 92 or the 89... they are massive beasts of knowledge.

And if I was home or could remember anything from any of my calc classes, I'd do that on paper.

And if I was home or could remember anything from any of my calc classes, I'd do that on paper.

dbaryl

09-30-2002, 04:25 PM

Originally posted by BMJ

Ok, then tell me mister TI-92... can you tell if the derivative expression for

y = sin(x^(1/2))+(sin(x)^(-1/2))is

[cos(x^(1/2))]/[2x^(1/2)] + 1/[2(sin(x)^(1/2))]:confused: Yup, I can, just watch ;)

Attached you'll find a screenshot of an emulater TI-92 Plus with that problem. Seems correct to me :)

As you can see, there's a MINUS and not a plus in there.

Ok, then tell me mister TI-92... can you tell if the derivative expression for

y = sin(x^(1/2))+(sin(x)^(-1/2))is

[cos(x^(1/2))]/[2x^(1/2)] + 1/[2(sin(x)^(1/2))]:confused: Yup, I can, just watch ;)

Attached you'll find a screenshot of an emulater TI-92 Plus with that problem. Seems correct to me :)

As you can see, there's a MINUS and not a plus in there.

Aran

09-30-2002, 05:58 PM

wow, that's one whacky emu, where'd you get it from?

dbaryl

09-30-2002, 06:05 PM

I think this link should do it:

http://www.ticalc.org/archives/files/fileinfo/84/8442.html

although I know I found it elsewhere. Emulates anything from 82 to 92+, with the right roms. The download on that page includes all of these.

I actually own a 92 (which I hate cause of it's size) as well as a 89 and 83. I think there's no real need for the 92 in any case, 89 can do it all just as well, except for QWERTY keyboard and some memory. Plus, an emulator doesn'r really care how much "memory" you have now, does it? ;)

[edit]

http://www.google.com/search?q=Virtual+TI

lots more links there... thanks google :)

There's some sweet stuff here (http://www.technoplaza.net/programming/index.cgi?p=vti), as well as a programming tutorial for TIGCC, a version of C for TI.

http://www.ticalc.org/archives/files/fileinfo/84/8442.html

although I know I found it elsewhere. Emulates anything from 82 to 92+, with the right roms. The download on that page includes all of these.

I actually own a 92 (which I hate cause of it's size) as well as a 89 and 83. I think there's no real need for the 92 in any case, 89 can do it all just as well, except for QWERTY keyboard and some memory. Plus, an emulator doesn'r really care how much "memory" you have now, does it? ;)

[edit]

http://www.google.com/search?q=Virtual+TI

lots more links there... thanks google :)

There's some sweet stuff here (http://www.technoplaza.net/programming/index.cgi?p=vti), as well as a programming tutorial for TIGCC, a version of C for TI.

BMJ

09-30-2002, 09:32 PM

We should have an emulator contest!

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