Comments on: Differentiate Inverse Cos – Proof

By: admin

admin — Tue, 08 May 2012 11:11:38 +0000

@No
Look back at the start:
We are trying to differentiate the function y = cos-1(x) but this is equivalent to cosy = x (by definition of cos-1)
So then where we ave cos^2(y) in the line above it becomes x^2 by substitution

By: No

No — Sun, 06 May 2012 23:16:30 +0000

Oh Come on!!! I got it all the way till “dy/dx = -1/√(1-cos2y)” but then you said “but cosy = x so… dy/dx =- 1/√(1-x2)”, Not clear on how and why it is. You didn’t explain how you went from that to this dy/dx =- 1/√(1-x2)????
Thanks

By: trevorpythag

trevorpythag — Mon, 09 Feb 2009 17:51:40 +0000

oops sorry thanks for pointing it out
dave

By: Barbara

Barbara — Sun, 08 Feb 2009 22:07:05 +0000

You’ve missed the minus!!!
d/dy(arccos) = – 1/ sq(1-x^2)

By: Nadya Fermega

Nadya Fermega — Wed, 14 Jan 2009 09:53:40 +0000

@Denaya

No no no, you are wrong Denaya, rohedi’s comment corresponds to your purpose is at this address

http://unapologetic.wordpress.com/2008/10/13/sine-and-cosine/

when Mr. Rohedi solves f”+f=0

I think you have done big blunder, huahuahau…sorry honey.

By: Nadya Fermega

Nadya Fermega — Wed, 14 Jan 2009 09:52:15 +0000

@Denaya

No no no, you are wrong Denaya, rohedi’s comment corresponds to your purpose is at this address

http://unapologetic.wordpress.com/2008/10/13/sine-and-cosine/

when Mr. Rohedi solves f”+f=0

I think you have done big blunder, huahuahau…

By: Denaya Lesa

Denaya Lesa — Wed, 14 Jan 2009 09:42:33 +0000

Hmm, if you want to know an application of both cos-1(x) and sin-1(x) simultaneously, please read rohedi’s comment on

http://unapologetic.wordpress.com/2008/10/10/the-exponential-differential-equation/.

By: Denaya Lesa

Denaya Lesa — Wed, 14 Jan 2009 09:20:13 +0000

He he he, I think you must take the following conclusions:

the differentiate of cos-1(x) is dy/dx = – 1/√(1-x2)

while

the differentiate of sin-1(x) is dy/dx = 1/√(1-x2)

How about you all?