CBSE > Class 11 > Mathematics | CBSE Board | Homework Help

sinx + sin3x + sin5x = 0 »(sinx + sin5x) + sin3x = 0 Using the formula sinA + sinB = 2sin(A+B/2)cos(A-B/2) we get »2sin3x*cos2x + sin 3x = 0 Taking sin3x common, »sin3x(2cos2x+1) = 0 »sin3x = 0 or 2cos2x+1 = 0 sin 3x = sin 0 or cos2x = -1/2 » 3x = nπ + (-1)^n (0) or cos2x = cos 2π/3 » x = nπ/3 or x = (2nπ ± 2π/3)/2 » x = nπ/3 or x = nπ ± π/3

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2x+3y≥6, x-2y≤2 ,6x+4y≤24, -3x+2y≤3, x≥0 , y≥0

Posted by Vaishali Choudhary 4 years, 6 months ago

CBSE > Class 11 > Mathematics

0 answers

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2n-1 pn, 2n+1Pn-1=22:7

Posted by Gunjan Sharma 4 years, 6 months ago

CBSE > Class 11 > Mathematics

0 answers

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Find the number of terms in the expansion of (a+b + c)^n

Posted by Anubhav Raj 4 years, 6 months ago

CBSE > Class 11 > Mathematics

0 answers

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Cosbeta into cos 2alpha minus beta equal to

Posted by Dev Tandon 4 years, 6 months ago

CBSE > Class 11 > Mathematics

0 answers

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The smallest set A such that A U ( 3,5 ) = (1,2,3,5,4 )

Posted by Swetha Swetha 4 years, 6 months ago

CBSE > Class 11 > Mathematics

4 answers

Sathi Gupta 4 years, 6 months ago

1,2 and 4 is fixed but 3 and 5 may be

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Suman Chaudhary 4 years, 6 months ago

1,2 and 4

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Hemant Kumar Bahrod 4 years, 6 months ago

{1,2&4}

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Pujan Sharma 4 years, 6 months ago

1,2&4

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The smallest set A such that A U (3,5) =(1,2,3,5,4)

Posted by Swetha Swetha 4 years, 6 months ago

CBSE > Class 11 > Mathematics

1 answers

Sathi Gupta 4 years, 6 months ago

1,2 and 4 is fixed but 3 and 5 may be

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x+y≥1,x≤5,y≤4,2x+3y≤12,x≥0,y≥0

Posted by Vaishali Choudhary 4 years, 6 months ago

CBSE > Class 11 > Mathematics

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A solution of 9% acid is to be diluted by adding 3% acid solution to it. The resulting mixture is to be more than 5% but less than 7% acid. If there is 460 litres of the 9% solution, how many litres of 3% solution will have to be added?

Posted by Vaishali Choudhary 4 years, 6 months ago

CBSE > Class 11 > Mathematics

1 answers

Gaurav Seth 4 years, 6 months ago

Let x Lot 3% solution be added to 460 L of 9% solution of acid.
Then, total quantity of mixture = (460 + x) L

Hence, the number of litres of the 3% solution of acid must be more than 230 and less than 920.

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how many element has P(A)=nil

Posted by Krishna Padole 4 years, 6 months ago

CBSE > Class 11 > Mathematics

3 answers

Krishna Padole 4 years, 6 months ago

thanks for answer

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Sathi Gupta 4 years, 6 months ago

1 is correct

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Sushmitha Acharya 4 years, 6 months ago

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If one children get 25% marks in a exàm and then he fail in a exàm by 25 marks while other student get 50%marks in a exàm ànd he pass by 50 màrks on a exàm .so whàt is the màximum number in the exam?

Posted by Anushka Singh 4 years, 6 months ago

CBSE > Class 11 > Mathematics

1 answers

Krishna Padole 4 years, 6 months ago

ans

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let a and b be two sets such that the sets a×b and b×a have an element in common of the sets a and b have an element in common

Posted by Exquisite Lo.. 4 years, 6 months ago

CBSE > Class 11 > Mathematics

1 answers

Gaurav Seth 4 years, 6 months ago

Important formulas :

A ∪ B = B ∪ A

A ∪ (B ∪ C) = (A ∪ B) ∪ C.

Let A and B have x elements in common .

n { (A ∩ B) × (B ∪ A) } = n { (A × B) ∩ (B × A)

⇒ n { (A ∩ B) × (B ∪ A) } = n { (A ∩ B) } × n{ (A ∩ B) }

⇒ n { (A ∩ B) × (B ∪ A) } = k × k ⇒ k²

Hence A × B and B × A have an element in common . The number of elements is k² provided that k is the number of elements in common in A and B .

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Find the co-ordinates of the focii , the vertices , length of conjugate axis, length of transverse axis ,the eccentricity and the length of latus rectum of hyperbola represented by the equation ? 2 − 16? 2 = 16

Posted by Dev Gulati 4 years, 6 months ago

CBSE > Class 11 > Mathematics

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Let A = {x : x is positive integral multiple of 3 less than 31} and B = { x : x is prime number less than 30}, Then n(AUB) + n(AՈB) is equal to: *

Posted by Nitin Kumar 4 years, 6 months ago

CBSE > Class 11 > Mathematics

2 answers

Prachi Janwani 4 years, 6 months ago

A = {6,12,18,24,30} B = {2,3,5,7, 11,13,17,19,23,29} AUB = {2, 3,5,6,7,11,12,13,17,18,19,23,24,29,30} n(AUB) = 15 A interaction B = 0 n(A international B) = 0 n(AUB) +n(A interaction B) = 15+0 = 15

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Yogita Ingle 4 years, 6 months ago

S={x:x is a positive multiple of 3 less than 31}

⟹S={3,6,9,12,⋯,30}

⟹n(S)=10

P={x:x is a prime number less than 30}

⟹P={2,3,5,7,11,13,17,19, 23, 29}

⟹n(P)= 10

n(S)+n(P)=10+10=20

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A intersection ( A complement intersection B complement )

Posted by Mahak Gupta 4 years, 6 months ago

CBSE > Class 11 > Mathematics

3 answers

Sathi Gupta 4 years, 6 months ago

Null set Suman is correct

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Suman Chaudhary 4 years, 6 months ago

Because, if A = 1,2,3,4 and B = 3,4,5,6 and U = 1,2,3,4,5,6,7,8 , Now A' intersection B' = 7,8 And A intersection ( A' intersection B') = phy

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Suman Chaudhary 4 years, 6 months ago

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Value of tan 40degrees

Posted by Hemansh Kesariya 4 years, 6 months ago

CBSE > Class 11 > Mathematics

0 answers

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Value of tan40degree

Posted by Hemansh Kesariya 4 years, 6 months ago

CBSE > Class 11 > Mathematics

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If Y={x: x is a positive factor of the number 2^p-1(2^p-1) is a prime number }.Write Y in the roaster form.

Posted by Gm Keerthana 4 years, 6 months ago

CBSE > Class 11 > Mathematics

2 answers

Sushmitha Acharya 4 years, 6 months ago

Hai gm

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Gaurav Seth 4 years, 6 months ago

Y- {x | x is a positive factor of the number 2^P-1(2^P – 1), where 2^P – 1 is a prime number}.
So, the factors of 2^P-1 are 1,2,2²,2³,…, 2^{P- 1}.
Y= {1,2,2²,2³, …,2 ,2^p-1}.