Practicing Success
If $a^4 +\frac{1}{a^4} = 194$, then what is the value of $\frac{a^6+1}{a^3}$ ? |
46 50 52 48 |
52 |
If x4 + \(\frac{1}{x^4}\) = a then x2 + \(\frac{1}{x^2}\) = \(\sqrt {a + 2}\) = b and x + \(\frac{1}{x}\) = \(\sqrt {b + 2}\) According to the question, $a^4 +\frac{1}{a^4} = 194$ then a2 + \(\frac{1}{a^2}\) = \(\sqrt {194 + 2}\) = 14 and a + \(\frac{1}{a}\) = \(\sqrt {14 + 2}\) = 4 If x + \(\frac{1}{x}\) = n then, $x^3 +\frac{1}{x^3}$ = n3 - 3 × n $\frac{a^6+1}{a^3}$ = 43 - 3 × 4 = 52 |