Question

if x=root7 +root3 and xy=4, then x^4 + y^4 is?

Answer 1

Answer:

ignore my handwriting......

Answer 2

Answer:

x⁴+y⁴ =368

Step-by-step explanation:

Given  :-

xy =4         y = 4/X

x=  √7+√3

To find:

x⁴+y⁴ = ?

Solution:

so y = 4/(√7+√3)

Multiply numerator and denominator by (√7-√3)

y =   4/(√7-√3) /(√7+3)(√7-√3)

= y = (√7-√3)

we know a²+b² (a+b)²-2ab

x⁴+y⁴ = (x²+y²)² -2x²y²

=(x²+y²)²-2(xy)²

= [(√7+√3)² + (√7-√3)²]² -2 (4²)

= [7+3+2√7.√3+7+3-2√7.√3]²-32

= 20-32

=400-32

=368

x⁴+y⁴ =368