HOW DUS THIS STRIKE???

12 Answers

1
skygirl ·

is it C....

but i am getting a line and a crve[which is not a circle]......

21
tapanmast Vora ·

sky, pl. give da the equation of ur line n ur curve

it is not da rite answer though

1
skygirl ·

x3+y3+3xy-1 =0

=> (x+y)3 - 3xy(x+y) +3xy -1 =0

=> (x+y)3-1 = 3xy(x+y) - 3xy

=> (x+y-1)(x2+y2+2xy +1 +x +y) = 3xy(x+y-1)

=> (x+y-1)[x2+y2 - xy +1 +x +y] = 0

21
tapanmast Vora ·

ON THE RITE TRACK!!!!

do thoda jumbling

33
Abhishek Priyam ·

may be (A)

21
tapanmast Vora ·

BINGO! as always!!!

give da pt.

line is clear frm sky x+y=1

33
Abhishek Priyam ·

that 2 degree... is a point (-1,-1)
solve it as a quadratic and D≤0
so D=0 for x-=-1 y=-1

21
tapanmast Vora ·

HAAA abhi yaad aaya!!!

ther is a way to find da exact pt. par uski zaroorat nahi hai

C this u'll get how :

33
Abhishek Priyam ·

This is one of the example of some must see problems...Q.3

http://targetiit.com/iit_jee_forum/posts/some_must_see_problems_155.html

33
Abhishek Priyam ·

hahah :D

utna mat yaad rakho...

they are just second degree.. solve it as quadratic.... and interpret from there....

21
tapanmast Vora ·

ANOTHER methd :

[x^2+y^2 - xy +1 +x +y] has to be 0

and v can c that the eqtn is symmetric wid x and y

so it bcums

x^ + 2x + 1 = (x+1)2 = 0

ther4 x = -1 = y

thnx PRiyam n Sky [1]

33
Abhishek Priyam ·

hmm.... yes.. is question me symmetry tah dekhe hi nahi... [3]

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