Home » Ask & Discuss » Mathematics. » Differential Calculus « Back to Discussion

Differential Calculus

Blazing goIITian

Joined:	22 Aug 2007
Post:	339

18 Apr 2008 18:39:53 IST

0 People liked this

740

find dy/dx

None

sin(x+y)=log(x+y)

Share this article on:

Comments (6)

RyuAmakusa

Blazing goIITian

Joined: 21 Mar 2008

Posts: 776

18 Apr 2008 19:24:39 IST

Like 1 people liked this

put x+y=t now dy/dx +1 = dt/dx

and sin t =log t so t=e^sin t . now diff.

dt/dx = e^sin t.* cost * dt/dx. ......

now cant u get it.

purnima naik

New kid on the Block

Joined: 8 Mar 2008

Posts: 19

19 Apr 2008 20:54:22 IST

Like 1 people liked this

sin(x+y)=log(x+y) then sinxcosy+cosxsiny=log(x+y) then dy/dx(cosxcosy-sinxsiny)+(cosxcosy-sinxsiny)=1/x+y(1+dy/dx) ,then [cos(x+y)-1/x+y]dy/dx=1/x+y-cos(x+y) then dy/dx= -[1-cos(x+y)(x+y)/1-cos(x+y)(x+y)] then dy/dx= -1

BALGANESH

Blazing goIITian

Joined: 21 Dec 2007

Posts: 1025

19 Apr 2008 21:04:35 IST

Like 1 people liked this

differentiate both sides
cos(x+y) [ 1+dy/dx] = 1/(x+y) [ 1+ dy/dx]
cos(x+y) + cos(x+y) dy/dx = [1+dy/dx/ (x+y)
(x+y) cos(x+y) + (x+y) cos(x+y) dy/dx = 1 + dy/dx
dy/dx [ (x+y) cos(x+y) -1] = 1 - (x+y) cos(x+y)
dy/dx = - [ (x+y)cos(x+y) -1] / [(x+y) cos(x+y) -1]
= - 1

varsha valli g.

Blazing goIITian

Joined: 31 Jan 2007

Posts: 515

19 Apr 2008 21:04:47 IST

Like 1 people liked this

simple.....

sin(x+y)-log(x+y)=0
diff, cos(x+y) * (1+y') - (1/(x+y) )*(1+y')=0
(1+y')[cos(x+y)-(1/(x+y))=0
y'=-1

!!!!!!!!!!!!!!!!!!!!!

Siva kumar B

New kid on the Block

Joined: 8 Apr 2008

Posts: 21

22 Apr 2008 12:29:24 IST

Like 1 people liked this

Sin(x+y)=log(x+y)
Sin(x+y)-log(x+y)=0
Cos(x+y)[1+dy/dx]-1/(x+y)[1+dy/dx]=0
[1+dy/dx]{cos(x+y)-1/(x+y)}=0
==1+dy/dx=0
=dy/dx=-1

y`=-1

rate me

zee.......

Blazing goIITian

Joined: 22 Aug 2007

Posts: 339

5 Nov 2008 21:39:41 IST

Like 0 people liked this

----moderated

Quick Reply

Reply

	Some HTML allowed.
	Keep your comments above the belt or risk having them deleted.
	Signup for a avatar to have your pictures show up by your comment
	If Members see a thread that violates the Posting Rules, bring it to the attention of the Moderator Team