Explore topic-wise InterviewSolutions in Current Affairs.

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1.

ILLUSTRATIVE EXAMPLESCheck which o the following are solutions o the equation x-2y = 4 and which areEXAMPLE 1not:(iii)(4,0)(iv)(Q.4V2)bd(1,1)

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ii) as 2 -0 is not equal to 4iv) as sqrt2 - 2× 4sqrt2 = - 7sqrt2 not equal to 4v) as 1-2 = -1 is not equal to 4

how 7 sqrt2

we get that because sqrt2 - 8sqrt2 = -7sqrt2

2.

(Illustrative Exam(ivIV

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3.

2ト60tiveroveint

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4.

Using principle of mathematical induction, prove the followrove the following for alln(n+1) (2n +1)112+34 + ....... +n" =+2

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hi friend I don't know the answer of this question and please like my answer

I will solve your problem if you like this

5.

ROVE THAT

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6.

A right circular cylinder just encloses a sphere of radius r (see figure).Find:surface area of the sphere(i) curved surface area of the cylinder(ii) ratio of the areas obtained in (i) and (ii)

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7.

A right circular cylinder just encloses a sphere of radius r (see figure).Find: (i) surface area of the sphere(i) curved surface area of the cylinder(ii) ratio of the areas obtained in (i) and (ii)

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8.

rove thatCot A!-tan A

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1+secA. cosecA LHS =RHS

9.

(07,12,1१ -- 3१(A) 22, 26(C) 280) 29

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the series is.7,7+5, 12+5+2, 19+5+2+2, 28+5+2+2+2. therefore answer is 28.

2+2+2+5+28+2, 2+2+5+19, 2+5+12, 5+7+7 =25

the right answer is 28

the right answer of question is 28

28

10.

le.9.11 rove that V3 is irrational.

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Let us assume that √3 is a rational number.

then, as we know a rational number should be in the form of p/q where p and q are co- prime number.

So,√3 = p/q { where p and q are co-prime}√3q = p

Now, by squaring both the side

we get,(√3q)² = p²3q² = p² ........ ( i )

So,if 3 is the factor of p²then, 3 is also a factor of p ..... ( ii )

=> Let p = 3m { where m is any integer }

squaring both sidesp² = (3m)²p² = 9m²

putting the value of p² in equation ( i )3q² = p² 3q² = 9m²q² = 3m²

So,if 3 is factor of q²then, 3 is also factor of q

Since, 3 is factor of p & q bothSo, our assumption that p & q are co-prime is wrong

hence, √3 is an irrational number

11.

A right circularcylinder just encloses a sphere ofjustg. 13.22). Findsurface area of the sphere,curved surface area of the cylinder,ratio of the areas obtained in (i) and (Gi)ra(it)Fg, 132

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12.

A right circular cylinder just encloses a sphere ofradius r (see Fig. 13.22). Find0) surface area of the sphere,(i) curved surface area of the cylinder(ii) ratio of the areas obtained in (i) and (ii).9.

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13.

9.A right circular cylinder just encloses a sphere ofradius r (see Fig. 13.22). Find) surface area of the sphere,()curved surface area of the cylinder,(ii) ratio of the areas obtained in (i) and (ii).Fig, 13.22

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14.

A right circular cylinder just encloses a sphere ofradius r (see Fig. 13.22). Find0 surface area of the sphere,i) curved surface area of the cylindert) ratio of the areas obtained in (i) and (i),9.

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15.

A right circular cylinderjust encloses a sphere ofradius r (see Fig. 13.22). Find0 surface area of the sphere,(ii) curved surface area of the cylinder,(Gi) ratio of the areas obtained in (i) and (ii).s. Fig. 132

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16.

9.A right circular cylinder just encloses a sphere ofradius r (see Fig. 13.22). Find(6) surface area of the sphere,(D) curved surface area of the cylinder,(ii) ratio of the areas obtained in (i) and (ii).Fig, 13.22

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17.

(a) 25 (b) 26 (c) 29 (u)21

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18.

Let the vertex of an angle ABC be located outside a circle and let the sides of the angleintersect equal chords AD and CE with the circle. Prove that ZABC is equal to half thedifference of the angles subtended by the chords AC and DE at the centre.

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19.

22.2rove

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20.

(Illustrative Examples)rovethat)

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21.

Que, H. Find the interval in whichf(2 -xx)=xe is increasing.

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we can differentiate y wrt x and check its value is positive.

dy/dx= e^-x*x(2-x)nowdy/dx is positive when x(2-x) is positive as e^{-x} is always positive.

x (2 - x) is positive if 0 < x < 2 .

Hence y is increasing in the interval (0, 2)

22.

0.rove that sin 30 +

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23.

rove that 5 is irrational.

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Let us assume that√5 is a rational number.

We know that the rational numbers are in the form of p/q form where p, q are integers.so,√5 = p/q p =√5q

We know that 'p' is a rational number. So√5 q must be rational since it equals to pbut it doesnt occurs with√5 since its not an integer

Therefore, p =/=√5q

This contradicts the fact that√5 is an irrational numberhence our assumption is wrong and√5 is an irrational number.

24.

rove that V5 is irrational

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Let us assume, to the contrary, that √5 is rational. i.e, we can find integer a and b such that √5= a/b.suppose a and b have a common factor other than 1,then we can divide by the common factor and assume that a and b are coprime. So, b√5=a.Squaring on both side, and rearranging, we get 5b^2=a^2.

Therefore , a^2 is divisible by 5, and by Theorem 1.3, it follows that a is also divisible by 3.So, we can write a =3c for some integer c. Substituting for a, we get 5b^2=25c^2, i.e , b^2 =3c^2.This means that b^2 is divisible by 5 and so b is also divisible by 5. Therefore, a and b have at least 5 as a common factor. But this contradicts the fact that a and b are coprime. This contradiction has arisen because of our incorrect assumption that √5 is rational. So, we conclude that √5 is irrational.

25.

B(2, 8), find the value ofIf the point (m, 3) lies on the line segment joining the points6 nd B(2, 8), ind the value of m

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26.

( 2 a - b ) ^ 2 %2B 2 ( 2 a - b ) - 8

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27.

8(a-2 b)^{2}-2 a+4 b-1

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8(a-2b)(a-2b)-2(a-2b)-1suppose x=2a-b8x*x-2x-1=8x*x-4x+2x-1=4x(2x-1)+1(2x-1)=(4x+1)(2x-1)=(8a-4b+1)(2a-4b-1)

28.

Example 1. Prove thatcot θ + tan θ =cosec θ sec θ

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29.

Find the surface area obtained by revolving y= 3x, xe[0,2] about y axis.

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30.

Example 1: Prove that in two concentric circles,the chord of the larger circle, which touches thesmaller circle, is bisected at the point of contact.

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31.

rove that:l. sin+ cos

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32.

a) 26c) 2b) 2d) 28

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The answer of question is b)

the answer is B is right

The right answer is 'B'

33.

ind the distance between the points:(0) A(9, 3) and B(15, 11)(i) A-6,-4) and B(9,-12) (iv) A(1, -3) and B(4, -6)(ii) A(7,-4) and B(-5,1)a+b,a-b)and a-b, a+b)(vi) P(asin o., acos a) and Q(acos a,- asin a)

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Distance between pointsP(a+b, a-b) and Q(a-b, a+b)

D = sqrt[(a-b-a-b)^2 + (a+b-a+b)] = sqrt[(-2b)^2 + (2b)^2] = sqrt(4b^2 + 4b^2) = sqrt(8b)^2 = 2sqrt(2)b

34.

- Let the vertex of an angle ABC be located outside a circle and let the sidesof the angle intersect equal chords AD and CE with the circle. Prove thatABC is equal to half the difference of the angles subtended by the chordsAC and DE at the centre.

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Given:AD = CE

To prove:∠ABC = 1/2(∠DOE –∠AOC)

In△AOD and△COE

AD = CE (Given)

AO = OC and DO = OE (Radii of same circle)

∴△AOD ≅ △COE (By SSS congruence criterion)

⇒∠1 =∠3,∠2 =∠4 (CPCT) ....(i)

But OA = OD and OC = OE ⇒∠1 =∠2 and∠3 =∠4 .....(ii)

From (i) and (ii), we have

∠1 =∠2 =∠3 =∠4 (= x say)

Also, OA = OC and OD = DE

⇒∠7 =∠8 (= z say) and∠5 =∠6 (= y say)

Now, ADEC is a cyclic quadrilateral

⇒∠DAC +∠DEC =180°

⇒ x + z + x + y =180° ⇒ y =180°- 2x - z ...(iii)

In△DOE,∠DOE = 180° - 2y

and in△AOC,∠AOC = 180° - 2z

∴∠DOE -∠AOC = (180° - 2y) - (180° - 2z) = 2z - 2y

= 2z - 2(180° - 2x - z) (Using (iii))

= 4z + 4x - 360° ....(iv)

Again, ∠BAC + ∠CAD = 180° ⇒∠BAC = 180°– (z + x) ....(v)

Similarly, ∠BCA = 180°– (z + x) ....(vi)

In△ABC,∠ABC =180° -∠BAC - ∠BCA

=180° - 2[180° - (z - x)] (Using (v) and (vi))

= 2z + 2x -180° = 1/2(4z + 4x - 360°) ....(vii)

From (iv) and (vii), we have

∠BAC = 1/2(∠DOE - ∠AOC)

35.

10-[15—{8-6-8-2)}]

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10-[15-{8-6-8-2}]=10-[15-{-8}]=10-[15+8]=10-23=-13

36.

and OS areExample 3 : In Fig. 6.11, OP, OQ, ORfourrays. Prove that POQ+ QOR+ SOR +4 POS 360°

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37.

6 + ( 8 - 2 )

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6+(8-2)=6+6=12(5+3)-(4*2)8-8=0

38.

EXAMPLE 3 The sides BA and DC of a quadrilateral ABCD are produced as shown inFig. 13.3. Prove that a+bax+y

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Thanks alot

39.

Example 3 : In Fig. 10.32, AB is a diameter of the circle, CD is a chord equal to theradius of the circle. AC and BD when extended intersect at a point E. Prove thatAEB 60°

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40.

EXAMPLE 1 Prove that 3 is an irrational number.

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Let us assume that √3 is a rational number.

then, as we know a rational number should be in the form of p/q

where p and q are co- prime number.

So,

√3 = p/q { where p and q are co- prime}

√3q = p

Now, by squaring both the side

we get,

(√3q)² = p²

3q² = p² ........ ( i )

So,

if 3 is the factor of p²

then, 3 is also a factor of p ..... ( ii )

=> Let p = 3m { where m is any integer }

squaring both sides

p² = (3m)²

p² = 9m²

putting the value of p² in equation ( i )

3q² = p²

3q² = 9m²

q² = 3m²

So,

if 3 is factor of q²

then, 3 is also factor of q

Since

3 is factor of p & q both

So, our assumption that p & q are co- prime is wrong

hence,. √3 is an irrational number

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41.

Find xe ds

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42.

ved Examples:1 : Find the area of triangle ABC whose verticesare A(3,2), B(-2,-8)and C(6,-10).

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43.

In a quadrilateral ABCD, CO and DO are the bisectors of C and ZD respectrove that LCOD =-(LA + LB).

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44.

Q.17 A median of a triangle divides it into two triangles of equal areas. Verify this result for triangle ABC whosevertices are A (4,-6), B (3,-2) and C (5, 2)

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45.

Using the method of integration find the area of the triangle ABC, coordinateswhose vertices are A(2, 0), B (4, 5) and C (6, 3).

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1

2

3

46.

Find the equation of the median AD ofthe Δ ABC whose vertices are A(2, 5)B(-4, 9) and C(-2, -1).

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47.

Using vectors find the area of ∆ABC whose vertices are A(1, 2, 3)B(2,-1,4) and C(4, 5, -1).

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48.

Find the area of the triangle whose vertices are (3.2) (-2, -3) and (2, 3).

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49.

Find the centroids of the triangle whose vertices are ( - 7, 6 ) , ( 2 , - 2 ) , ( 8,5 )

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Centroid = (x1+x2+x3)/ 3, (y1+y2+y3)/3= (-7+2+8)/3 , (6-2+5)/3 = 3/3 , 9/3 = 1,3

So,centroid = (1,3)

50.

Find the centroids of the triangle whose vertices are ( - 7, 6 ) , ( 2 , - 2 ) , ( 8,5 )

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centroid = (x1+x2+x3/3 , y1+y2+y3/3)

= -7+2+8/3 , 6-2+5/3

= 3/3 , 9/3

= 1,3