実数(問題③)

問題

問1.\(x=\sqrt{2}+\sqrt{3}\)とする.このとき,次の式を計算せよ.

(1) \(\displaystyle x+\frac{1}{x}\)

(2) \(\displaystyle x^2+\frac{1}{x^2}\)

(3) \(\displaystyle x^3+\frac{1}{x^3}\)

(4) \(\displaystyle x^4+\frac{1}{x^4}\)

問2.\(\displaystyle x=\frac{1}{\sqrt{5}+1},\displaystyle y=\frac{1}{\sqrt{5}-1}\)とする.このとき,次の式を計算せよ.

(1) \(x+y\)

(2) \(x-y\)

(3) \(xy\)

(4) \(x^2+y^2\)

(5) \(x^2-y^2\)

(6) \(x^3+y^3\)

(7) \(x^3-y^3\)

(8) \(x^4-y^4\)

解答