関数 $y = (x^2 - x + 1)(x^2 + x + 2)$ を微分せよ。解析学微分関数の微分積の微分2025/7/271. 問題の内容関数 y=(x2−x+1)(x2+x+2)y = (x^2 - x + 1)(x^2 + x + 2)y=(x2−x+1)(x2+x+2) を微分せよ。2. 解き方の手順積の微分公式 (uv)′=u′v+uv′(uv)' = u'v + uv'(uv)′=u′v+uv′ を用いる。ここで、u=x2−x+1u = x^2 - x + 1u=x2−x+1、v=x2+x+2v = x^2 + x + 2v=x2+x+2 とおく。まず、uuu と vvv をそれぞれ微分する。u′=ddx(x2−x+1)=2x−1u' = \frac{d}{dx}(x^2 - x + 1) = 2x - 1u′=dxd(x2−x+1)=2x−1v′=ddx(x2+x+2)=2x+1v' = \frac{d}{dx}(x^2 + x + 2) = 2x + 1v′=dxd(x2+x+2)=2x+1次に、積の微分公式に当てはめる。y′=u′v+uv′y' = u'v + uv'y′=u′v+uv′y′=(2x−1)(x2+x+2)+(x2−x+1)(2x+1)y' = (2x - 1)(x^2 + x + 2) + (x^2 - x + 1)(2x + 1)y′=(2x−1)(x2+x+2)+(x2−x+1)(2x+1)y′=(2x3+2x2+4x−x2−x−2)+(2x3−2x2+2x+x2−x+1)y' = (2x^3 + 2x^2 + 4x - x^2 - x - 2) + (2x^3 - 2x^2 + 2x + x^2 - x + 1)y′=(2x3+2x2+4x−x2−x−2)+(2x3−2x2+2x+x2−x+1)y′=(2x3+x2+3x−2)+(2x3−x2+x+1)y' = (2x^3 + x^2 + 3x - 2) + (2x^3 - x^2 + x + 1)y′=(2x3+x2+3x−2)+(2x3−x2+x+1)y′=4x3+4x−1y' = 4x^3 + 4x - 1y′=4x3+4x−13. 最終的な答えy′=4x3+4x−1y' = 4x^3 + 4x - 1y′=4x3+4x−1