IIT JEE , AIEEE Forum - Mathematics , Analytical Geometry

magiclko

What is the equation of the line passing thru (2,2) and having equal intercepts on th axis??

PS : I knw the answer is very easy.... but watevr options were given thr.... x+y=4 wasnt thr .....

ashish_banga

the equation is

x/a + y/b = 1
a = x-intercept
b = y- intercept

acc to the ques.
x/a + y/a = 1
x +y = a
also x + y =4 as it passes thru (2,2)
so ,x + y = 4

magiclko

i said beforhand only.... this wasnt thr in the options...

himanshu2006

since ,THE LINE IS EQUALLY INCLINED TO BOTH AXES.
THEREFORE ,ITS SLOPE WOULD BE 1 OR -1.
NOW,
FIRST EQN.:--

Y-2= 1(X-1)
X=Y OR X-Y=0
SEC.EQN:

Y-2=-1(X-2)
X+Y = 4

PLZ LET ME KNOW WHERE I WENT WRONG'
CHEERS!!!!

HIMANSHU

magiclko

u rnt wrong nehwhere... but this wasnt thr in the options given!!

himanshu2006

CAN U PLZ GIVE ME THE OPTIONS SO THAT I CAN CHECK WHERE I WENT WRONG

vineet

hey dont worry may be options in book r wrong.sometimes it happens

rohitju

yep ,

i got

x+y=4

there must be something wrong with the options.

magiclko

the answer given was x=y.... while solving x+y=4 shud be the only answer

wat i meant to ask here is that are "zero intercepts justified".... i hav asked it frm experts also... see the following post

http://www.goiit.com/posts/list/1846.htm#6864

Asmita

Obviously there are 2 correct ans. : x=y & x+y=4.

Asmita

Let the eq. of the required line in the intercept form be x/a

y/b =

1.

Case 1 : when x/a + y/b =1 i.e. the line is going downwards from the left to the right of the cartesian plane.

Here a=b=k(say)

therefore x+y=k

but (2,2) lies on it Therefore 2+2=k=4

therefore the eq. of the line is x+y=4.

Case 2 :when x/a - y/b =

1 i.e. the line is going upwards from the left to the right of the cartesian plane.

Here a=b=p(say)

therefore l(x-y)l=p....(1)

but (2,2) lies on it Therefore 2-2=p=0

therefore from (1) the eq. of the line is x-y=0 i.e. x=y

shubham_sachdeva

DEAR MAGICLKO,

I HAVE ASKED SOME1 .HE IS SAYING THAT 0 INTERCEPTS R NOT DEFINED.

magiclko

i think its not defined.... but is not sure..... waise, in the question , only x=y was given and not x+y=4, so it must be true!!!

shubham_sachdeva

OPTIONS CAN ALSO BE WRONG

UR QNS. ANS. WAS GIVEN IN FUNDA OF 0 INTERCEPT

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