IIT JEE , AIEEE Forum - Mathematics , Analytical Geometry

ashish_banga

the point $({a}^{2} , a +1 )$ liis in the angle between the lines 3x -y + 1 =0 and x +2y - 5 =0 containg the origin , then find thee range of a

Decoder

just plot the lines in a graph... the most suitable method..

now just see the area...
on which side of L1 does tht area lie ..choose a point from that area and see the nature of sign u get on putting tht ordered pair...

repeat the same for L2...

now take intersection of the soln. u get.from both..

fro L1 ---- ( -INF. , 0) U ( 1/3, INF.)
FRO L2 --- ( -INF ,-3 ) U ( 1, INF.)

Taking int.

L2 forms the range..

sriram.a

plot the lines on the graph.

you will get the point of intersection as (3/7,16/7)

as given ( ${a}^{2}$ ,a+1)lies on the side containing (0,0).

so, ${a}^{2}$ =(0,+infinity),a+1=(-infinity,16/7)

now solve for a

a=(-infinity,9/7

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