If x−1x=7, find the value of x3−1x3.
x−1x=7
Cubing both sides,
(x−1x)3=(7)3⇒ x3−1x3−3(x−1x)=343⇒ x3−1x3−3×7=343⇒ x3−1x3−21=343⇒ x3−1x3=343+21=364
If x+1x=5, find the value of x3+1x3.
If x+1x=7 then find the value of x3+1x3