Math, asked by megha9826, 1 year ago

√5 + 1 / √5 - 1 + √5 - 1 / √5 + 1 = a + b√5 Find the values of a and b .

Answers

Answered by abhi178
13
Is your question like \mathbf{\frac{\sqrt{5}+1}{\sqrt{5}-1}+\frac{\sqrt{5}-1}{\sqrt{5}+1}}=\mathbf{a+b\sqrt{5}}
Okay, Let's start to solve !

Plz do rationalisation of \mathbf{\frac{\sqrt{5}+1}{\sqrt{5}-1}} and \mathbf{\frac{\sqrt{5}-1}{\sqrt{5}+1}} separately .
e.g., \mathbf{\frac{\sqrt{5}+1}{\sqrt{5}-1}} × \mathbf{\frac{\sqrt{5}+1}{\sqrt{5}+1}}
= \mathbf{\frac{(\sqrt{5}+1)^2}{\sqrt{5}^2-1}}
= (5 + 1 + 2√5)/(5 - 1)
= (6 + 2√5)/4
= (3 + √5)/2

similarly, \mathbf{\frac{\sqrt{5}-1}{\sqrt{5}+1}} × \mathbf{\frac{\sqrt{5}-1}{\sqrt{5}-1}}
= \mathbf{\frac{(\sqrt{5}-1)^2}{\sqrt{5}^2-1}}
= (5 + 1 - 2√5)/(5 - 1)
= (3 - √5)/2

Now, (3 + √5)/2 + (3 - √5)/2 = a + b√5
(3 + √5 + 3 - √5)/2 = a + b√5
3 = a + b√5
3 + 0.√5 = a + b√5
Compare both sides,
a = 3 and b = 0
Answered by ravindrabansod26
7

Answer:

Step-by-step explanation:

Is your question like  

Okay, Let's start to solve !

Plz do rationalisation of  and  separately .

e.g.,  ×  

=  

= (5 + 1 + 2√5)/(5 - 1)

= (6 + 2√5)/4

= (3 + √5)/2

similarly,  ×  

=  

= (5 + 1 - 2√5)/(5 - 1)

= (3 - √5)/2

Now, (3 + √5)/2 + (3 - √5)/2 = a + b√5

(3 + √5 + 3 - √5)/2 = a + b√5

3 = a + b√5

3 + 0.√5 = a + b√5

Compare both sides,

a = 3 and b = 0

thank you

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