EAMCET Engineering 2001 Solved Paper

Given pair of straight lines is
ax2+2hxy+by2=0
Here, ‌‌m1=2m2‌‌ (given) . . . (i)
Since, ‌‌m1+m2=‌

−2h

b

. . . (ii)
and ‌‌m1m2=‌

a

b

. . . (iii)
From Eqs. (i) and (ii)
2m2+m2‌=−‌

2h

b

3m2‌=‌

−2h

b

. . . (iv)
From Eqs. (i) and (iii)
2m2⋅m2‌=‌

a

b

2m22‌=‌

a

b

. . . (v)
From Eqs. (iv) and (v)
2(‌

−2h

3b

)2‌=‌

a

b

2⋅‌

4h2

9b2

‌=‌

a

b

8h2‌=9ab