MCQMediumJEE 2026Basics: Distance, Section Formula, Locus

JEE Mathematics 2026 Question with Solution

Among the statements

(S1): If A(5,1)A(5,-1) and B(2,3)B(-2,3) are two vertices of a triangle whose orthocentre is (0,0)(0,0), then its third vertex is (4,7)(-4,-7).

(S2): If positive numbers 2a,b,c2a, b, c are three consecutive terms of an A.P., then the lines ax+by+c=0ax+by+c=0 are concurrent at (2,2)(2,-2).

  • A

    both are correct

  • B

    only (S2) is correct

  • C

    both are incorrect

  • D

    only (S1) is correct

Answer

Correct answer:A

Step-by-step solution

Standard Method

Given:

  • In (S1), A(5,1)A(5,-1) and B(2,3)B(-2,3) are two vertices of a triangle and the orthocentre is H(0,0)H(0,0).
  • In (S2), 2a,b,c2a, b, c are three consecutive terms of an A.P. and the family of lines is ax+by+c=0ax+by+c=0.

Find: Whether statements (S1) and (S2) are correct.

For (S1), verify whether the third vertex (4,7)(-4,-7) gives orthocentre at the origin.

Slope of ABAB is

3(1)25=47=47\frac{3-(-1)}{-2-5}=\frac{4}{-7}=-\frac{4}{7}

So the altitude from CC must have slope

74\frac{7}{4}

Now slope of the line joining C(4,7)C(-4,-7) to H(0,0)H(0,0) is

0(7)0(4)=74\frac{0-(-7)}{0-(-4)}=\frac{7}{4}

Hence, CHCH is perpendicular to ABAB.

Next, slope of BCBC is

734(2)=102=5\frac{-7-3}{-4-(-2)}=\frac{-10}{-2}=5

So the altitude from AA must have slope

15-\frac{1}{5}

The slope of AHAH is

0(1)05=15\frac{0-(-1)}{0-5}=-\frac{1}{5}

Hence, AHAH is perpendicular to BCBC.

Also, slope of CACA is

1(7)5(4)=69=23\frac{-1-(-7)}{5-(-4)}=\frac{6}{9}=\frac{2}{3}

So the altitude from BB must have slope

32-\frac{3}{2}

The slope of BHBH is

030(2)=32\frac{0-3}{0-(-2)}=-\frac{3}{2}

Hence, BHBH is perpendicular to CACA.

Therefore, all three altitudes pass through H(0,0)H(0,0), so (S1) is correct.

For (S2), since 2a,b,c2a, b, c are consecutive terms of an A.P.,

b2a=cb b-2a=c-b

Therefore,

2b=2a+c2b=2a+c

Now test the point (2,2)(2,-2) in the line

ax+by+c=0ax+by+c=0

Substituting x=2x=2 and y=2y=-2,

2a2b+c=02a-2b+c=0

Using 2b=2a+c2b=2a+c,

2a(2a+c)+c=02a-(2a+c)+c=0

So the equation is satisfied identically. Hence every such line passes through (2,2)(2,-2), so (S2) is correct.

Therefore, both statements are correct. The correct option is A.

Common mistakes

  • Using the incorrect relation OA+OB+OC=OH\vec{OA}+\vec{OB}+\vec{OC}=\vec{OH} for the orthocentre. This vector identity is not valid in general for a triangle. Instead, verify the orthocentre by checking that each altitude is perpendicular to the opposite side.

  • Forgetting that perpendicular slopes satisfy m1m2=1m_1 m_2=-1 when both slopes are defined. In (S1), the statement should be checked through altitude-side perpendicularity, not by comparing arbitrary segments.

  • In (S2), writing the A.P. condition incorrectly. Since 2a,b,c2a, b, c are consecutive terms of an A.P., the middle term condition is 2b=2a+c2b=2a+c. Use this relation before substituting into the line equation.

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