与えられた15個の関数をそれぞれ $x$ で微分する問題です。

解析学微分導関数多項式冪関数
2025/5/29

1. 問題の内容

与えられた15個の関数をそれぞれ xx で微分する問題です。

2. 解き方の手順

微分は、以下の公式を用いて行います。
- (xn)=nxn1(x^n)' = nx^{n-1}
- 定数項の微分は0
- 和の微分は、それぞれの項の微分の和
以下に、各関数の微分を示します。
(1) y=x7y = x^7
y=7x71=7x6y' = 7x^{7-1} = 7x^6
(2) y=3x2y = -3x^2
y=32x21=6xy' = -3 \cdot 2x^{2-1} = -6x
(3) y=4x3y = 4x^3
y=43x31=12x2y' = 4 \cdot 3x^{3-1} = 12x^2
(4) y=x3+x2+x+1y = x^3 + x^2 + x + 1
y=3x2+2x+1+0=3x2+2x+1y' = 3x^2 + 2x + 1 + 0 = 3x^2 + 2x + 1
(5) y=3x2+2x+1y = 3x^2 + 2x + 1
y=32x+2+0=6x+2y' = 3 \cdot 2x + 2 + 0 = 6x + 2
(6) y=5x5+3x3+xy = 5x^5 + 3x^3 + x
y=55x4+33x2+1=25x4+9x2+1y' = 5 \cdot 5x^4 + 3 \cdot 3x^2 + 1 = 25x^4 + 9x^2 + 1
(7) y=14x22xy = -\frac{1}{4}x^2 - \frac{2}{x}
y=14x22x1y = -\frac{1}{4}x^2 - 2x^{-1}
y=142x2(1)x2=12x+2x2y' = -\frac{1}{4} \cdot 2x - 2(-1)x^{-2} = -\frac{1}{2}x + \frac{2}{x^2}
(8) y=0.2x5+0.5x6y = -0.2x^5 + 0.5x^6
y=0.25x4+0.56x5=x4+3x5y' = -0.2 \cdot 5x^4 + 0.5 \cdot 6x^5 = -x^4 + 3x^5
(9) y=x3+x510y = -x^3 + \frac{x^5}{10}
y=3x2+5x410=3x2+x42y' = -3x^2 + \frac{5x^4}{10} = -3x^2 + \frac{x^4}{2}
(10) f(x)=10000f(x) = -10000
f(x)=0f'(x) = 0
(11) f(x)=353f(x) = 35^3
f(x)=0f'(x) = 0
(12) f(x)=4x35xf(x) = 4x^3 - 5x
f(x)=43x25=12x25f'(x) = 4 \cdot 3x^2 - 5 = 12x^2 - 5
(13) f(x)=4x45x+2f(x) = 4x^4 - 5x + 2
f(x)=44x35+0=16x35f'(x) = 4 \cdot 4x^3 - 5 + 0 = 16x^3 - 5
(14) f(x)=13x312f(x) = \frac{1}{3}x^3 - \frac{1}{2}
f(x)=133x20=x2f'(x) = \frac{1}{3} \cdot 3x^2 - 0 = x^2
(15) f(x)=0.4x2+13xf(x) = -0.4x^2 + \frac{1}{3}x
f(x)=0.42x+13=0.8x+13f'(x) = -0.4 \cdot 2x + \frac{1}{3} = -0.8x + \frac{1}{3}

3. 最終的な答え

(1) y=7x6y' = 7x^6
(2) y=6xy' = -6x
(3) y=12x2y' = 12x^2
(4) y=3x2+2x+1y' = 3x^2 + 2x + 1
(5) y=6x+2y' = 6x + 2
(6) y=25x4+9x2+1y' = 25x^4 + 9x^2 + 1
(7) y=12x+2x2y' = -\frac{1}{2}x + \frac{2}{x^2}
(8) y=x4+3x5y' = -x^4 + 3x^5
(9) y=3x2+x42y' = -3x^2 + \frac{x^4}{2}
(10) f(x)=0f'(x) = 0
(11) f(x)=0f'(x) = 0
(12) f(x)=12x25f'(x) = 12x^2 - 5
(13) f(x)=16x35f'(x) = 16x^3 - 5
(14) f(x)=x2f'(x) = x^2
(15) f(x)=0.8x+13f'(x) = -0.8x + \frac{1}{3}