Question

if x-1/x=6 then find the value of x square +21/x square and x 4 +1/x4​

Answer 1

x - 1/x = 6

squaring on both sides

x² + 1/x² - 2(x)(1/x) = 36

=> x² + 1/x² = 38

squaring on both sides

x⁴ + 1/x⁴ + 2(x⁴)(1/x⁴) = 1444

=> x⁴ + 1/x⁴ = 1442