AP EAMCET2009MathematicsPair of Lines
The area (in square unit) of the triangle formed by x+y+1=0 and the pair of straight lines x^2-3 x y+2 y^2=0 is
Options
- A7 12
- B5 12
- C1 12
- D1 6
Correct answer
C. 1 12
Step-by-step solution
aligned Given, & & x^2-2 x y-x y+2 y^2 & =0 & & (x-2 y)(x-y) & =0 aligned On solving Eqs. (i) and (ii), we get A (- 2 3 ,- 1 3 ), B (- 1 2 ,- 1 2 ), C(0,0) Area of A B C= 1 2 | array ccc - 2 3 & - 1 3 & 1 - 1 2 & - 1 2 & 1 0 & 0 & 1 array |= 1 2 [ 1 3 - 1 6 ]= 1 2 [ 1 6 ]= 1 12