Question

If (x-y) =13 and xy =5 then find the value of 1/3 (x√2+y√2

Answer 1

First we take x + y = 5

sq. on both sides

⇒(x+y)

2

=(5)

2

⇒x

2

+y

2

+2xy=25

⇒13+2xy=25[x

2

+y

2

=13](given)

⇒2xy=25−13=12

⇒xy=

2

12

=6