Question

If a = ✓ 5 + 1 / ✓5 - 1 and b = ✓ 5 - 1 / ✓ 5 + 1 , find the value of a² + ab + b² / a² - ab + b² CLASS 9 WB BOARD FROM COMPLETE MATHEMATICS​

Answer 1

Answer:

Correct option is

A

3

4

Here ab=1

& (a+b)=

5

−1

5

+1

+

5

+1

5

−1

⇒(a+b)=

4

(

5

+1)

2

+(

5

−1)

2

=

4

5+1+2

5

+5+1−25

⇒

(a+b)=3

(a

2

+b

2

)=(a+b)

2

−2ab

=9−2=7

∴

a

2

+b

2

−ab

a

2

+b

2

+ab

=

7−1

7+1

=

3

4

Step-by-step explanation:

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