JEE Main & Advanced
Mathematics
Straight Line
Question Bank
Slope of line, Equation of line in different forms
question_answer
The ends of the base of an isosceles triangle are at \[(2a,\ 0)\]and\[(0,\ a).\] The equation of one side is \[(lx+my)(a+b)=(l+m)\ ab\] The equation of the other side is
A) \[x+2y-a=0\]
B) \[x+2y=2a\]
C) \[3x+4y-4a=0\]
D) \[3x-4y+4a=0\]
Correct Answer:
D
Solution :
Obviously, other line AB will pass through (0, a) and \[(2a,k)\]. But as we are given \[AB=AC\] \[\Rightarrow k=\sqrt{4{{a}^{2}}+{{(k-a)}^{2}}}\]Þ \[k=\frac{5a}{2}\] Hence the required equation is \[3x-4y+4a=0\].