pls solve..

question edited::
find the no. of positive integral pairs of the solution of (x+y)/(1-xy) = 3

i know this shud be in algebra but actually this is one step of an inverse trig. question....
options:
(a) one (b) zero (c) two (d) none of these

10 Answers

1
skygirl ·

none of these?? (threea re there)

21
tapanmast Vora ·

X=tan(p)
Y=tan(q)

LHS = tan(p+q);

p+q = tan-13

tan-1x + tan-1y = tan-13;

u can take it frm then on.....

106
Asish Mahapatra ·

how are there integral solutions?

1
skygirl ·

i got three !!

1
skygirl ·

(3,0) , (-1, -2) , (-2, -1)

21
tapanmast Vora ·

y not, (0,3) thn

1
skygirl ·

no no not (3,0) .... i meant (0,3) only...

106
Asish Mahapatra ·

the actual question was :

the number of positive integral solutions of the equation
tan-1x + cos-1y/√1+y2 = sin-13/√10

I simplified to tan-1x + tan-1y = tan-13
i.e. (x+y)/(1-xy) = 3

but i think positive integral solutions is zero....

i dont know answer this was a question in Brilliant's test 2day.... thx sky....

1
skygirl ·

well...

i dunno wat u did then...

do it simply naa...

separate y and x terms:

u will get y= 3-x/1+3x

now, see for which x, u get integral y's...

there wont be many as u can c, bcoz x>0 or <-2 will give a fraction..

3
iitimcomin ·

X+Y = 3 - 3XY ..........

FRM HERE U CAN DO IT GRAPHICALLY .......

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