question_answer

Equations of diagonals of square formed by lines \[x=0,\] \[y=0,\]\[x=1\] and \[y=1\]are                                         [MP PET 1984]

A)            \[y=x,\ y+x=1\]                      

B)            \[y=x,\ x+y=2\]

C)            \[2y=x,\ y+x=\frac{1}{3}\]  

D)            \[y=2x,\ y+2x=1\]

Correct Answer: A

Solution :

           Co-ordinates of the vertices of the square are \[A(0,\,0),\] \[B(0,\,1),\] \[C(1,\,1)\] and \[D(0,\,1)\].                    Now the equation of AC is \[y=x\] and of \[BD\] is \[y-1=-\frac{1}{1}(x-0)\] \[\Rightarrow x+y=1\].