Math, asked by NITESH761, 21 days ago

Solve this Interesting problem. don't give meaningless answers I will report.If you can't solve it don't answer it.​

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Answers

Answered by tennetiraj86
2

Step-by-step explanation:

Given :-

1/(1+√2) + 1/(√2+√3) +1/(√3+√4)+ ...

+ 1/(√8+√9)

To find :-

Find the value of the given numerical expression?

Solution :-

Given numerical expression is

1/(1+√2) + 1/(√2+√3) +1/(√3+√4)+ ...

+ 1/(√8+√9)

The denominator in 1/(1+√2) = 1+√2

The Rationalising factor of 1+√2 = 1-√2

On Rationalising the denominator of

1/(1+√2) then

=> [1/(1+√2)]×[(1-√2)/(1-√2)]

=> (1-√2)/[(1+√2)(1-√2)]

=> (1-√2)/[1²-(√2)²]

Since (a+b)(a-b) = a²-b²

Where , a = 1 and b = √2

=> (1-√2)/(1-2)

=> (1-√2)/(-1)

=> -(1-√2)

=> -1+√2

=> √2-1

1/(1+√2) = √2-1 --------------------(1)

The denominator in 1/(√2+√3) = √2+√3

The Rationalising factor of √2 +√3 is √2+√3

On Rationalising the denominator of

1/(√2+√3)

=> [1/(√2+√3)]×[(√2-√3)/(√2-√3)]

=> (√2-√3)/[(√2+√3)(√2-√3)]

=> (√2-√3)/[(√2)²-(√3)²]

Since (a+b)(a-b) = a²-b²

Where , a = √2 and b = √3

=> (√2-√3)/(2-3)

=> (√2-√3)/(-1)

=> -(√2-√3)

=> -√2+√3

=> √3-√2

1/(√2+√3) = √3-√2 --------------------(2)

The denominator in 1/(√3+√4) = √3+√4

The Rationalising factor of √3+√4 is √3-√4 then

On Rationalising the denominator of

1/(√3-√4)

=> [1/(√3+√4)]×[(√3-√4)/(√3-√4)]

=> (√3-√4)/[(√3+√4)(√3-√3)]

=> (√3-√4)/[(√3)²-(√4)²]

Since (a+b)(a-b) = a²-b²

Where , a = √3 and b = √4

=> (√3-√4)/(3-4)

=> (√3-√4)/(-1)

=> -(√3-√4)

=> -√3+√4

=> √4-√3

1/(√3+√4) = √4-√3 --------------------(3)

and the same way

The denominator in 1/(√8+√9) = √8+√9

The Rationalising factor of √8+√9 is √8-√9

On Rationalising the denominator of

1/(√8+√9)

=> [1/(√8+√9)]×[(√8-√9)/(√8-√9)]

=> (√8-√9)/[(√8+√9)(√8-√9)]

=> (√8-√9)/[(√8)²-(√9)²]

Since (a+b)(a-b) = a²-b²

Where , a = √8 and b = √9

=> (√8-√9)/(8-9)

=> (√8-√9)/(-1)

=> -(√8-√9)

=> -√8+√9

=> √9-√8

1/(√8+√9) = √9-√8 --------------------(4)

On adding all equations then we get

=>√2-1+√3-√2+√4-√3+√5-√4+√6-√5

+√7-√6+√8-√7+√9-√8

=>-1 + (√2-√2)+(√3-√3)+(√4-√4)+(√5-√5) +(√6-√6)+(√7-√7)+(√8-√8)+√9

=> -1+√9

=> -1+3

=> 3-1

=> 2

Answer:-

The value of the given expression for the given problem is 2

Used formulae:-

  • The Rationalising factor of √a+b is √a-b

  • The Rationalising factor of √a+√b is √a -√b

  • (a+b)(a-b) = a²-b²
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