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Given √2 is irrational number. Let √2 = a / b wher a,b are integers b ≠ 0 we also suppose that a / b is written in the simplest form Now √2 = a / b ⇒ 2 = a2 / b2 ⇒ 2b2 = a2 ∴ 2b2 is divisible by 2 ⇒ a2 is divisible by 2 ⇒ a is divisible by 2 ∴ let a = 2c a2 = 4c2 ⇒ 2b2 = 4c2 ⇒ b2 = 2c2 ∴ 2c2 is divisible by 2 ∴ b2 is divisible by 2 ∴ b is divisible by 2 ∴a are b are divisible by 2 . this contradicts our supposition that a/b is written in the simplest form Hence our supposition is wrong ∴ √2 is irrational number.

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The height and radius of the cone of which the frustum is a part are h1 and r1 respectively and h2 : h1= 1:2 then r2:r1 is equal to

Posted by Gupta Shivaay 6 years, 11 months ago

CBSE > Class 10 > Mathematics

1 answers

Himanshi Sharma 6 years, 11 months ago

Given:-Height nd radius of frustum are h1 nd r1 respectively. h2/h1=1/2 .·. r2/r1=1/2 Since,All the linear dimensions of similar figures are in the same retio.

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If cos A +cos square A=1 then find the value of sin square A and sin4 A

Posted by Harman Taneja 6 years, 11 months ago

CBSE > Class 10 > Mathematics

1 answers

Gupta Shivaay 6 years, 11 months ago

Cos A = 1- sin²A = Cos²A Sin²A+sin⁴A = cosA + cos²A (given) = 1

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The diameter of a roller is 84cm and its length is 120 centimetre.Its take 500 complete Revolution to move once over to level the playground area of the playground in metres is

Posted by Nitin Kumar 6 years, 6 months ago

CBSE > Class 10 > Mathematics

1 answers

Sia ? 6 years, 6 months ago

2r = 84 cm, r = 42 cm, h = 120 cm
⇒ r = 42 cm., h = 120 cm
∴ Area of the playground leveled in taking 1 complete revolution.
= {tex}2\pi rh{/tex}
= {tex}2\times{22\over7}\times42\times120{/tex}= 31680 cm²
∴ Area of the playground = 31680 × 500
= 15840000 cm²

={tex}15840000\over100\times100{/tex} m²
= 1584 m2
∴ the area of the playground is 1584 m²

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ANSWER

Show me 2014 board exam paper

Posted by Ashish Yadav 6 years, 11 months ago

CBSE > Class 10 > Mathematics

2 answers

Ram Kushwah 6 years, 11 months ago

DOWNLOAD FROM:

https://www.vedantu.com/previous-year-question-paper/cbse-maths-class-10-year-2014

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Ashish Yadav 6 years, 11 months ago

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If A, B and C are interior angles of triangle ABC then show that cos(B+C/2)=sinA/2

Posted by Anushka Saha 6 years, 11 months ago

CBSE > Class 10 > Mathematics

4 answers

Neha Sirur 6 years, 11 months ago

Hope u ll get it

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Yogita Ingle 6 years, 11 months ago

In a triangle, sum of all the interior angles
A + B + C = 180°
⇒ B + C = 180° - A
⇒ (B+C)/2 = (180°-A)/2
⇒ (B+C)/2 = (90°-A/2)
⇒ sin (B+C)/2 = sin (90°-A/2)
⇒ sin (B+C)/2 = cos A/2

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Neha Sirur 6 years, 11 months ago

In a triangle abc we know that all three angles is equal to 180° so angle a +b+c=180. Now shift a on the other side i.e. b+c=180-a next divide both sides by 2 so it gives (b+c) /2= 90-a/2. further on put cos on both sides ---. Cos (b+c)/2= cos 90-a/2 and cos 90-a/2 = sin a/2. So substitute it and we get cos (b+c)/2 = sin a/2

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Anushka ? 6 years, 11 months ago

Cos(B+C/2) CAN BE WRITTEN AS Sin(90-B+C/2)...by taking the L. C. M, we will get Sin(180-B+C/2) and we know that in a triangle 180-B+C/2 is equal to A . So, our answer will be SinA/2.

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Find AP whose nth term is 3n-5.

Posted by Dhruv Vishnoi 6 years, 11 months ago

CBSE > Class 10 > Mathematics

1 answers

Yogita Ingle 6 years, 11 months ago

nth term = 3n - 5
First term = a₁ = 3 x 1 - 5 = -2
Second term = a₂ = 3 x 2 - 5 = 1
Third term = a₃ = 3 x 3 - 5 = 4
Thus, the AP is -2, 1, 4, ......

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Please anybody send me the date sheet for final board exam of 10th

Posted by Priyansh Goyal 6 years, 11 months ago

CBSE > Class 10 > Mathematics

3 answers

Ram Kushwah 6 years, 11 months ago

You can download from :

http://cbse.nic.in/newsite/circulars/2018/Class-X_datesheet.pdf

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@ Aashu 6 years, 11 months ago

It is given in google..

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Anshika Pal???? 6 years, 11 months ago

March 7 -maths 13- science 19- hindi 23- english 29- ss

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Evaluate..cot12°cot38°cot52°cot60°cot78°

Posted by Kabita Beura 6 years, 11 months ago

CBSE > Class 10 > Mathematics

4 answers

Himanshi Sharma 6 years, 11 months ago

1/root3

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Ram Kushwah 6 years, 11 months ago

cot12cot38cot52cot60cot78

=cot(90-78)cot(90-52)cot52cot60cot78

=tan78cot78 x tan52cot52 x cot60

=1x1x1 x cot60

={tex}\frac{1}{\sqrt3}{/tex}

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Vaishnavi Singh 6 years, 11 months ago

1/√3

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Vishal Gorana 6 years, 11 months ago

1/√3

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ANSWER

Formula of find a class mark

Posted by Lakshya Prabha 6 years, 11 months ago

CBSE > Class 10 > Mathematics

1 answers

Chetna Pandey 6 years, 11 months ago

Lower limit + Upper limit/2

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ANSWER

2y_12y_432 factories

Posted by Rajesh Chauhan 6 years, 11 months ago

CBSE > Class 10 > Mathematics

3 answers

Chetna Pandey 6 years, 11 months ago

Factories ?

2Thank You

Sanchita Sahoo 6 years, 11 months ago

I think it should be written as factorize....??

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Sanchita Sahoo 6 years, 11 months ago

y=18 or y= -12......

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ANSWER

(100/100)-(100/100)=2 Prove that

Posted by Vikas Prajapati 6 years, 11 months ago

CBSE > Class 10 > Mathematics

2 answers

Vikas Prajapati 6 years, 11 months ago

Saras bhidu

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Ram Kushwah 6 years, 11 months ago

Mr. Vikas these are useless things still for you I give the explaination

but for (100-100)/(100-100)

{tex}\begin{array}{l}=\frac{\displaystyle10^2-10^2}{10(10-10)}=\frac{(10-10)(10+10)}{10(10-10)}\\=\frac{10+10}{10}\\=\frac{\displaystyle20}{10}=2\\But\;this\;is\;coming\;because\;we\;used\;\frac{10-10}{10-10}=\;\frac00=1\;which\;is\;not\;possible,So\;such\;results\;are\;useless\end{array}{/tex}

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If the point (2,3) ,(4,4)and (6,_3) are co- linear then find the value of k

Posted by Sumit Das 6 years, 11 months ago

CBSE > Class 10 > Mathematics

3 answers

Ram Kushwah 6 years, 11 months ago

This question is Example 14 from chapter 7 page 169

Example 14 : Find the value of k if the points A(2, 3), B(4, k) and C(6, –3) are
collinear.
Solution : Since the given points are collinear, the area of the triangle formed by them
must be 0.

So {tex}\begin{array}{l}\frac12\lbrack2(k+3)+4(-3-3)+6(3-k)\rbrack=0\\\frac12(2k+6-24+18-6k)=0\\\frac12\times-4k=0\\or\;k=0\end{array}{/tex}

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Gaurav Seth 6 years, 11 months ago

Correct Question - Find the value of k if the points A(2,3) ,B(4,k) and C(6,-3) are collinear.

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Solution:

Given that A, B and C are collinear. Hence ar(DABC) = 0