Question

If N = V(√5+2)+v(√5-2)-√(3-2√2)÷
√ (√5 + 1)
then the value of N is​

Answer 1

Answer :

1 is the correct answer (option C)

Step by step explanation :

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Given, N = {√(√5 + 2) + √(√5 -2)}/√(√5 + 1) - √[3 – 2√2]

Now, {√[√5 + 2] +√[√5 – 2]}/√[√5 + 1]

= { √[√5 + 2] + √[√5 – 2] } √[√5 – 1] / (√[√5 + 1] √[√5 – 1])

= { √[(√5 + 2)(√5 – 1)] + √[(√5 – 2)(√5 – 1)] } / √[(√5 + 1)(√5 – 1)]

= { √[5 – √5 + 2√5 – 2] + √[5 – √5 – 2√5 + 2] } / √[5 – 1]

= { √[3 + √5] + √[7 – 3√5] } / 2

= { √[(6 + 2√5)/2] + √[(14 – 6√5)/2] } / 2

= { √[(1 + 5 + 2√5)/2] + √[(9 + 5 – 6√5)/2] } / 2

= { √[(1 + √5)2 /2] + √[(3 – √5)2 /2] } / 2

= { (1 + √5)/√2 + (3 – √5)/√2 } / 2

= { (1 + √5) + (3 – √5) } / (2√2)

= 4 / (2√2)

= √2

Again, √[3 – 2√2] = √[2 + 1 – 2√2]

= √[(√2 – 1)2 ]

= √2 – 1

Now, N = { √[√5 + 2] +√[√5 – 2] } / √[√5 + 1] – √[3 – 2√2]

=> N= √2 – (√2 – 1)

=> N= √2 – √2 + 1

=> N = 1