Home » Ask & Discuss » Class XII-Science
« Back to Discussion

Mathematics

Hot goIITian

Joined:	15 Feb 2012
Post:	180

4 May 2012 10:17:58 IST

1 People liked this

334

challenge

Engineering Entrance , JEE Main , CBSE Board , JEE Main & Advanced , Mathematics , Differential Calculus , CBSE XII (Science) , Mathematics I , Mathematics II

Siny = xsin(a+y) so proof

siny(dy/dx)-sin²(a+y)=0

Comments (4)

jagdish singh

Blazing goIITian

Joined: 19 Jan 2008

Posts: 1089

4 May 2012 18:59:36 IST

Like 0 people liked this

$\hspace{-16}\bf{\sin(y)=x.\sin(a+y)\Leftrightarrow x=\frac{\sin(y)}{\sin(a+y)}}$\\\\\\ Diff. both side w.r to $\bf{x}$, We Get\\\\\\ $\bf{\frac{dx}{dy}=\frac{\sin (a+y).\cos (y)-\sin (y).\cos(a+y)}{\sin^2(a+y)}}$\\\\\\ $\bf{\frac{dx}{dy}=\frac{\sin (a)}{\sin ^2(a+y)}}$\\\\\\ $\bf{\frac{dy}{dx}=\frac{\sin^2(a+y)}{\sin (a)}}$\\\\\\ $\bf{\sin (a).\frac{dy}{dx}-\sin^2(a+y)=0}$$

ronnie

Scorching goIITian

Joined: 18 Feb 2012

Posts: 264

4 May 2012 22:17:02 IST

Like 2 people liked this

1.Given,

siny=xsin(a+y)

or, 1/x=sin(a+y)/siny

or, 1/x=sinacoty+cosa

now differentiating both sides we get

-1/x2=-sinacosec2y.y’

From here we have the req. proof.

jagdish singh

Blazing goIITian

Joined: 19 Jan 2008

Posts: 1089

4 May 2012 23:05:17 IST

Like 0 people liked this

Great RonnieNice solution man....I have misread sin(a) instead of sin (y)

edison

Forum Expert

Joined: 19 Oct 2006

Posts: 7802

27 Sep 2012 17:43:17 IST

Like 0 people liked this

Well done Jagdish !!!

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