Q 11 :

Let the range of the function f(x)=6+16 cos x·cos(π3x)·cos(π3+x)·sin 3x·cos 6x, xR be [α, β]. Then the distance of the point (α, β) from the line 3x + 4y + 12 = 0 is:          [2025]

  • 8

     

  • 11

     

  • 9

     

  • 10

     

(2)

f(x)=6+16(14cos 3x) sin 3x·cos 6x

                                           [ cos θ cos(π3θ)cos(π3+θ)=14cos 3θ]

                =6+4 cos 3x sin 3x cos 6x=6+sin 12x

  Range of sin x = [–1, 1]

  Range of f(x) is [5, 7]

 (α,β)(5,7)

   Distance of point (5, 7) from the line 3x + 4y + 12 = 0

                =|15+28+125|=11



Q 12 :

Let the lines 3x – 4y – α= 0, 8x –11y – 33 = 0 and 2x – 3yλ = 0 be concurrent. If the image of the point (1, 2) in the line 2x – 3yλ = 0 is (5713,4013), then |αλ| is equal to          [2025]

  • 101

     

  • 113

     

  • 84

     

  • 91

     

(4)

As the three lines are concurrent,

      |34α8113323λ|=0

 3(11λ99)+4(8λ+66)α(24+22)=0

 33λ297+32λ+264+2α=0

 λ33+2α=0                                                    ...(i)

As image, (1, 2) w.r.t. 2x – 3yλ = 0 is (5713,4013)

       571312=401323=2(26+λ4+9)

 2213=2(4+λ)13  λ=7

Substitute λ = –7 in (i), we get

733+2α=0  a=13

  |αλ|=|13×(7)|=91



Q 13 :

Two equal sides of an isosceles triangle are along – x + 2y = 4 and x + y = 4. If m is the slope of its third side, then the sum, of all possible distinct values of m, is:          [2025]

  • 210

     

  • 12

     

  • –6

     

  • 6

     

(4)

Slope of given lines are m1=12 and m2=1.

Since, AB = AC, then ABC = ACB

Now, angle between AB and BC = angle between AC and BC

m121+12(m)=1m1m

 2m12+m=m+1m1

 2m23m+1=m2+3m+2

 m26m1=0

Sum of roots = 6

   Required sum is 6.



Q 14 :

Let the distance between two parallel lines be 5 units and a point P lie between the lines at a unit distance from one of them. An equilateral triangle PQR is formed such that Q lies on one of the parallel lines, while R lies on the other. Then (QR)2 is equal to _________.          [2025]



(28)

Let PRN=θ

 PR=cosec θ and PQ=4 sec(30°+θ)

For equilateral PQR.

Let PR = PQ

 cosec θ=4 sec(θ+30°)

 cos (θ+30°)=4 sin θ

 32cos θ12sin θ=4 sin θ

 tan θ=133

 cosecθ=28

Now, QR2=d2=cosec2θ=28.



Q 15 :

If α=1+r=16(3)r1 C2r112, then the distance of the point (12,3) from the line αx3y+1=0 is _________.         [2025]



(5)

Given, α=1+r=16(3)r1 C2r112

                    =1+r=16C2r112(3i)2r13i

Let t=3i, then we have

α=1+13i[C112t+C312t3+...+C1112t11]

        =1+13i[(1+3i)12(13i)122]

       =1+13i[(2ω2)12(2ω)122]=1         [ ω3=0]

   Distance of (12,3) from x3y+1=0 is

          |123(3)+1(1)2+(3)2|=123+11+3=5.



Q 16 :

The straight lines l1 and l2 pass through the origin and trisect the line segment of the line L: 9x+5y=45 between the axes. If m1 and m2 are the slopes of the lines l1 and l2, then the point of intersection of the line y=(m1+m2)x with L lies on           [2023]
 

  • y-x=5

     

  • 6x+y=10

     

  • y-2x=5

     

  • 6x-y=15

     

(1)

Let l1:y=m1x and l2:y=m2x be the two lines which trisects L.

Now, 9x+5y=45  x5+y9=1                 ...(i)

Now, L intersects coordinate axes at A(5,0) and B(0,9).

Since l1 divides AB in the ratio 2:1

  M(53,6)

Also, l2 divides AB in the ratio 1:2.

  N(103,3)

So, l1:6=m1×53m1=185
and l2:3=m2×103m2=910

So, equation of line y=(m1+m2)x becomes

y=(185+910)xy=92x              ...(ii)

Now point of intersection of (i) and (ii) is,

x5+x2=1  7x10=1  x=107 So, y=457

i.e., (107,457) is the point of intersection of (i) & (ii), which satisfies option (1).



Q 17 :

Let (α,β) be the centroid of the triangle formed by the lines 15x-y=82,6x-5y=-4 and 9x+4y=17. Then α+2β and 2α-β are the roots of the equation   [2023]

  • x2-7x+12=0

     

  • x2-10x+25=0

     

  • x2-14x+48=0

     

  • x2-13x+42=0

     

(4)

Given lines are

15x-y=82  (i)

6x-5y=-4  (ii)

9x+4y=17  (iii)

After solving the equations, we get the co-ordinates as (6,8),(1,2) and (5,-7)

So, centroid, (α,β)=(6+1+53,8+2-73)=(4,1)

  α+2β=4+2=6;  2α-β=7

So, required equation is x2-13x+42=0



Q 18 :

If (α,β) is the orthocenter of the triangle ABC with vertices A(3,-7), B(-1,2) and C(4,5), then 9α-6β+60 is equal to          [2023]

  • 30

     

  • 35

     

  • 25

     

  • 40

     

(3)

Draw altitudes BM, CN and AP, then their intersection point is the orthocentre.  

Now, let us find the equation of line BM, CN and AP.

Slope of AC=121

So, slope of BM=-112

Equation of BM: (y-2)=-112(x+1)

12y-24=-x-112y+x=23                ...(i)

Now, slope of AB=9-4

So, slope of CN=49

Equation of CN: (y-5)=49(x-4)9y-45=4x-16

 4x-9y-16+45=04x-9y+29=0  ...(ii)

Similarly, equation of AP: 5x+3y=-6  ...(iii)

Now, solving (i) and (ii), we get y=12157, x=-14157

Also, (-14157, 12157) satisfies (iii)

So, orthocentre, (α,β)=(-14157, 12157)

and 9α-6β+60=9×(-14157)-6×12157+60

=-42319-24219+114019=47519=25



Q 19 :

The combined equation of the two lines ax+by+c=0 and a'x+b'y+c'=0 can be written as (ax+by+c)(a'x+b'y+c')=0. The equation of the angle bisectors of the lines represented by the equation 2x2+xy-3y2=0 is               [2023]

  • 3x2+5xy+2y2=0

     

  • x2-y2-10xy=0

     

  • 3x2+xy-2y2=0

     

  • x2-y2+10xy=0

     

(2)

Given equation of lines is 2x2+xy-3y2=0 

Equation of angle bisector of lines ax2+2hxy+by2=0 is 

x2-y2xy=a-bh

Here, a=2, b=-3 and h=12

    Equation of angle bisector of given lines is

x2-y2xy=2+312=10

 x2-y2=10xy i.e., x2-y2-10xy=0



Q 20 :

A light ray emits from the origin making an angle 30° with the positive x-axis. After getting reflected by the line x+y=1, if this ray intersects the x-axis at Q, then the abscissa of Q is             [2023]

  • 2(3-1)

     

  • 32(3+1)

     

  • 23+3

     

  • 23-3

     

(3)

Given Slope of incident ray =tan30°=13

So, slope of incident ray = slope of reflected ray =13

Now, Equation of line making an angle 30° with positive x-axis and passing through origin is, y=x3

So, line y=x3 and x+y=1 intersect at (33+1,13+1)

So, equation of reflected ray is

y-13+1=3(x-33+1)

Put y=0 x=23+3



Q 21 :

Let B and C be the two points on the line y+x=0 such that B and C are symmetric with respect to the origin. Suppose A is a point on y-2x=2 such that ABC is an equilateral triangle. Then, the area of ABC is              [2023]

  • 23    

     

  • 83    

     

  • 33    

     

  • 103

     

(2)

Let point x=α lie on line y-2x=2  and point x=β lie on line y+x=0

Now, slope of AM=2+2αα=1

α=-2

      AM=22

And β=23

        AB=22×23=423

Area of ABC=34(AB)2=34×323=83



Q 22 :

A straight line cuts off the intercepts OA = a and OB = b on the positive directions of the x-axis and y-axis respectively. If the perpendicular from origin O to this line makes an angle of π6 with the positive direction of the y-axis and the area of OAB is 9833, then a2-b2 is equal to            [2023]

  • 3923

     

  • 1963

     

  • 196 

     

  • 98

     

(1)

Let the perpendicular distance be p.

The equation of the line AB is given as

xcosπ3+ysinπ3=p

 x·12+y32=p

 x2+y(23)=px2p+y2p3=1                       ...(i)

Intercept form of line AB will be xa+yb=1         ...(ii)
Comparing eq (i) and (ii), we get a=2p, b=2p3

Now, area of triangle OAB=9833

So, 12ab=983312×2p×2p3=9833 2p2=98

p2=49p=7    (p0)

    a=2×7=14,     b=2×73=143

   a2-b2=(14)2-(143)2=3923



Q 23 :

Let the equations of two adjacent sides of a parallelogram ABCD be 2x-3y=-23 and 5x+4y=23. If the equation of its one diagonal AC is 3x+7y=23 and the distance of A from the other diagonal is d, then 50d2 is equal to ________ .          [2023]



(529)

We have, 2x-3y=-23            (i)

                    5x+4y=23                (ii)

and              3x+7y=23               (iii)

Solve eqn. (i) and (iii), we get  A(-4,5)

Solve eqn. (ii) and (iii), we get  C(3,2)

Solve eqn. (i) and (ii), we get  B(-1,7)

Mid point of AC will be  (-12,72).

Equation of diagonal BD is

y-72=7/2-1/2(x+12)

 7x+y=0

Distance of A from diagonal BD is

d=|7×(-4)+5|49+1=2350

 50d2=(23)2=529



Q 24 :

If the line l1:3y-2x=3 is the angular bisector of the lines l2:x-y+1=0 and l3:αx+βy+17=0, then α2+β2-α-β is equal to ______ .      [2023]



(348)

Point of intersection of  l1:3y-2x=3 and l2:x-y+1=0 is P(0,1),

which lies on l3:αx+βy+17=0, β=-17

Consider a random point Q(-1,0) on l2:x-y+1=0

Image of point Q about  l1:2x-3y+3=0 is  Q'(-1713,613).

which can be calculated by the formula,

x-(-1)2=y-0-3=-2(-2+3)13

Now, Q' lies on l3:αx+βy+17=0

   α=7

Now, α2+β2-α-β=348



Q 25 :

The equations of the sides AB, BC and CA of a triangle ABC are: 2x+y=0, x+py=21a(a0) and x-y=3 respectively. Let P(2,a) be the centroid of ABC. Then (BC)2 is equal to _______ .         [2023]



(122)

2=1+α+β+33

  6=4+α+β

  α+β=2

  β=2-α    ...(i)

 C(5-α, 2-α)

Now, -2-2α+β3=a

  -2-2α+β=3aβ-2α=3a+2

  2-α-2α=3a+2

   α=-aβ=2+a

Point B, C lies on x+py=21a

So, α-2αp=21a -a+2ap=21a 2ap=22a

  pa=11a    ...(ii)

   p=11, a=0 (rejected)

and β+3+pβ=21a

5+a+p(2+a)=21a 5+a+2p+pa=21a

5+a+2p+11a=21a 2p+5=21a-12a

  2p+5=9a2×11+5=9a                   a=3

  Point B is (-3,6) and C(8,5)

  BC=(8+3)2+(5-6)2(BC)2=122



Q 26 :

A triangle is formed by the X-axis, Y-axis and the line 3x+4y=60. Then the number of points P(a,b) which lie strictly inside the triangle, where a is an integer and b is a multiple of a, is ______ .          [2023]



(31)

For point P(a,b) to lie strictly inside the triangle 3a+4b<60

Also a is an integer and b is a multiple of a

  b=na  3a+4na<60

        a(3+4n)<60

When a=1, 3+4n<60, n can take values 1,,14

When a=2, 2(3+4n)<60n can take values 1,2,,6 i.e. 6 point

When a=3, 3(3+4n)<60n can take values 1,2,,4 i.e. 4 point 

When a=4, 4(3+4n)<60n can take values 1,2 i.e. 2 point

When a=5, 5(3+4n)<60n can take values 1,2 i.e. 2 point

When a=6, 6(3+4n)<601 point

When a=7, 7(3+4n)<601 point

When a=8, 8(3+4n)<601 point 

Total number of points=14+6+4+2+2+1+1+1=31



Q 27 :

A triangle is formed by the tangents at the point (2, 2) on the curves y2=2x and x2+y2=4x, and the line x+y+2=0. If r is the radius of its circumcircle, then r2 is equal to __________ .              [2023]



(10)

Given curve S1:y2=2x and S2:x2+y2=4x

Point P(2,2) is common on S1 and S2

T1 is tangent to S1 at P

T1:2y=x+2

T1:x-2y+2=0

      T2 is tangent to S2 at P

T2:2x+2y=2(x+2)

T2:y=2

      Line L3:x+y+2=0

Now, PQ=a=20, QR=b=8, RP=c=6

Area of PQR=Δ=12×6×2=6

  r=abc4Δ=1604=10, r2=10



Q 28 :

A rectangle is formed by the lines x=0, y=0, x=3, and y=4. Let the line L be perpendicular to 3x+y+6=0 and divide the area of the rectangle into two equal parts. Then the distance of the point (12,-5) from the line L is equal to:                [2026]

  • 10

     

  • 25

     

  • 210

     

  • 310

     

(3)

Line is y=x3+C

Line passes thru (32,2)

2=12+CC=32

y=x3+32

6y=2x+9

Line is 2x-6y+9=0

Dist=|1+30+940|=40=210



Q 29 :

Let (α,β,γ) be the co-ordinates of the foot of the perpendicular drawn from the point (5,4,2) on the line r=(-i^+3j^+k^)+λ(2i^+3j^-k^). Then the length of the projection of the vector αi^+βj^+γk^ on the vector 6i^+2j^+3k^ is    [2026]

  • 18/7

     

  • 15/7

     

  • 3

     

  • 4

     

(1)

r=(-i^+3j^+k^)+λ(2i^+3j^-k^)

x+12=y-33=z-1-1=λ

Any general point P on the line is  

(2λ-1, 3λ+3, -λ+1)

Let the given point is A (5,4,2).

AP¯(2λ-6)i^+(3λ-1)j^+(-λ-1)k^

 AP¯rLine (L)

 AP¯·(2i^+3j^-k^)=0

2(2λ-6)+3(3λ-1)-1(-λ-1)=0

λ=1

α=1,  β=6,  γ=0

Let the vector u¯=αi^+βj^+γk^

                       u¯=i^+6j^+0k^

and  w¯=6i^+2j^+3k^

So projection=|u¯·w¯||w¯|=187



Q 30 :

Let a point A lie between the parallel lines L1 and L2 such that its distances from L1 and L2 are  6 and 3 units, respectively. Then the area (in sq. units) of the equilateral triangle ABC, where the points B and C lie on the lines L1 and  L2, respectively, is:    [2026]

  • 27

     

  • 156

     

  • 213

     

  • 122

     

(3)

sinθ=3a

sin(60°+θ)=9a

32cosθ+12sinθ=9a

31-9a2+3a=18a

a=84

Area of ABC=34a2=34×84=213



Q 31 :

Let A(1,0), B(2,-1) and C(73,43) be three points. If the equation of the bisector of the angle ABC is αx+βy=5, then the value of α2+β2 is             [2026]

  • 10

     

  • 5

     

  • 8

     

  • 13

     

(1)

BDDC=ABAC=2×352=35

D=(128,48)=(32,12)

Slope of AD=-3/21/2=-3

3x+y=5

α=3, β=1;  α2+β2=10



Q 32 :

If the image of the point P(1,2,a) in the line x-63=y-72=7-z2 is Q(5,b,c), then a2+b2+c2 is equal to           [2026]

  • 298

     

  • 264

     

  • 283

     

  • 293

     

(1)

Point M(3,b2+1,c+a2) satisfies the line

3-63=b2+1-72=c+a2-7-2

-1=b-124=c+a-14-4

b=8    ...(1) & c+a=18    ...(2)

Now PQL

(4i+(b-2)j+(c-a)k)·(3i+2j-2k)=0

12+2(b-2)-2(c-a)=0

6+(b-2)-(c-a)=0

b-c+a+4=0

8-c+a+4=0

c+a=12    ...(3)

From (2) & (3)

c=15,  a=3

So a2+b2+c2=9+64+225=298



Q 33 :

Let P(α,β,γ) be the point on the line x-12=y+1-3=z at a distance 414 from the point (1,-1,0) and nearer to the origin. Then the shortest distance between the lines x-α1=y-β2=z-γ3  and  x+52=y-101=z-31, is equal to             [2026]

  • 754

     

  • 274

     

  • 475

     

  • 457

     

(3)

Let P(2λ+1,-3λ-1,λ)

Then 4λ2+9λ2+λ2=16·14λ=±4-4  (nearer to origin)

 P(-7,11,-4)

 Shortest distance=|2-17123211||i^j^k^123211|

=281+25+9=475



Q 34 :

Let Q(a,b,c) be the image of the point P(3,2,1) in the line x-11=y2=z-11. Then the distance of Q from the line x-93=y-92=z-5-2 is.  [2026]

  • 5

     

  • 7

     

  • 8

     

  • 6

     

(2)

drs of PN=r-2, 2r-2, r

1(r-2)+2(2r-2)+1(r)=0

6r=6r=1

 N(2,2,2)

Q(1,2,3)

AQ=64+49+4=117

AM=|24+14-4|9+4+4=3417=217

 QM=117-68=49=7



Q 35 :

Let the angles made with the positive x-axis by two straight lines drawn from the point P(2, 3) and meeting the line x+y=6 at a distance 23 from the point P be θ1 and θ2. Then the value of (θ1+θ2) is:                    [2026]

  • π2

     

  • π3

     

  • π6

     

  • π12

     

(1)

Let Q is (23cosθ+2, 23sinθ+3)

so, x+y=6

23(cosθ+sinθ)+5=6

sinθ+cosθ=32

1+sin2θ=32

sin2θ=12

2θ=π6, 5π6

θ=π12, 5π6

So θ1+θ2=π2



Q 36 :

Let the line L pass through the point (−3,5,2) and make equal angles with the positive coordinate axes. If the distance of L from the point (−2,r,1) is 143, then the sum of all possible values of r is :    [2026]

  • 6

     

  • 16

     

  • 12

     

  • 10

     

(4)

Equation of line is : x+31=y-51=z-21=λ

 General point R on line is R(λ-3, λ+5, λ+2)

PR(λ-1, λ+5-r, λ+1)

Now PR·d=0

(λ-1)1+(λ+5-r)1+(λ+1)1=0

3λ-r+5=0

λ=r-53

  R(r-53-3, r-53+5, r-53+2)

R(r-143, r+103, r+13)

Now

PR=143    (PR)2=143

(r-143+2)2+(r+103-r)2+(r+13-1)2=143

(r-8)29+(10-2r)29+(r-2)29=143

(r2-16r+64)+(100+4r2-40r)+(r2-4r+4)=42

6r2-60r+126=0

r2-10r+21=0

r=3,7

Sum of possible values of r is 10