附录一 相关公式

附一  积分表及其相关公式

  1. k d x = k x + C ( k 是常数 ) , \displaystyle\int k\mathrm{d}x=kx+C\quad(k\text{是常数}),
  2. x μ d x = x μ + 1 μ + 1 + C ( μ 1 ) , \displaystyle\int x^\mu\mathrm{d}x=\cfrac{x^{\mu+1}}{\mu+1}+C\quad(\mu\ne-1),
  3. d x x = ln x + C , \displaystyle\int\cfrac{\mathrm{d}x}{x}=\ln|x|+C,
  4. d x 1 + x 2 = arctan x + C , \displaystyle\int\cfrac{\mathrm{d}x}{1+x^2}=\arctan x+C,
  5. d x 1 x 2 = arcsin x + C , \displaystyle\int\cfrac{\mathrm{d}x}{\sqrt{1-x^2}}=\arcsin x+C,
  6. cos x d x = sin x + C , \displaystyle\int\cos x\mathrm{d}x=\sin x+C,
  7. sin x d x = cos x + C , \displaystyle\int\sin x\mathrm{d}x=-\cos x+C,
  8. d x cos 2 x = sec 2 d x = tan x + C , \displaystyle\int\cfrac{\mathrm{d}x}{\cos^2x}=\displaystyle\int\sec^2\mathrm{d}x=\tan x+C,
  9. d x sin 2 x = csc 2 x d x = cot x + C , \displaystyle\int\cfrac{\mathrm{d}x}{\sin^2x}=\displaystyle\int\csc^2x\mathrm{d}x=-\cot x+C,
  10. sec x tan x d x = sec x + C , \displaystyle\int\sec x\tan x\mathrm{d}x=\sec x+C,
  11. csc x cot x d x = csc x + C , \displaystyle\int\csc x\cot x\mathrm{d}x=-\csc x+C,
  12. e x d x = e x + C , \displaystyle\int e^x\mathrm{d}x=e^x+C,
  13. a x d x = a x ln a + C , \displaystyle\int a^x\mathrm{d}x=\cfrac{a^x}{\ln a}+C,
  14. s h   x d x = c h   x + C , \displaystyle\int\mathrm{sh}\ x\mathrm{d}x=\mathrm{ch}\ x+C,
  15. c h   x d x = s h   x + C , \displaystyle\int\mathrm{ch}\ x\mathrm{d}x=\mathrm{sh}\ x+C,
  16. tan x d x = ln cos x + C , \displaystyle\int\tan x\mathrm{d}x=-\ln|\cos x|+C,
  17. cot x d x = ln sin x + C , \displaystyle\int\cot x\mathrm{d}x=\ln|\sin x|+C,
  18. sec x d x = ln sec x + tan x + C , \displaystyle\int\sec x\mathrm{d}x=\ln|\sec x+\tan x|+C,
  19. csc x d x = ln csc x cot x + C , \displaystyle\int\csc x\mathrm{d}x=\ln|\csc x-\cot x|+C,
  20. d x a 2 + x 2 = 1 a arctan x a + C , \displaystyle\int\cfrac{\mathrm{d}x}{a^2+x^2}=\cfrac{1}{a}\arctan\cfrac{x}{a}+C,
  21. d x x 2 a 2 = 1 2 a ln x a x + a + C , \displaystyle\int\cfrac{\mathrm{d}x}{x^2-a^2}=\cfrac{1}{2a}\ln|\cfrac{x-a}{x+a}|+C,
  22. d x a 2 x 2 = arcsin x a + C , \displaystyle\int\cfrac{\mathrm{d}x}{\sqrt{a^2-x^2}}=\arcsin\cfrac{x}{a}+C,
  23. d x x 2 + a 2 = ln ( x + x 2 + a 2 ) + C , \displaystyle\int\cfrac{\mathrm{d}x}{\sqrt{x^2+a^2}}=\ln(x+\sqrt{x^2+a^2})+C,
  24. d x x 2 a 2 = ln x + x 2 a 2 + C , \displaystyle\int\cfrac{\mathrm{d}x}{\sqrt{x^2-a^2}}=\ln|x+\sqrt{x^2-a^2}|+C,
  25. I n = 0 π 2 cos m u d u = 0 π 2 sin m u d u = { m 1 m m 3 m 2 1 2 π 2 , m 为正偶数, m 1 m m 3 m 2 2 3 , m 为大于1的正奇数, = { 1 3 5 ( m 1 ) 2 4 6 m ) π 2 , m 为正偶数, 2 4 6 ( m 1 ) 1 3 5 m , m 为大于1的奇数. \begin{aligned}I_n&=\displaystyle\int^{\frac{\pi}{2}}_0\cos^{m}u\mathrm{d}u=\displaystyle\int^{\frac{\pi}{2}}_0\sin^{m}u\mathrm{d}u\\&=\begin{cases}\cfrac{m-1}{m}\cdot\cfrac{m-3}{m-2}\cdot\cdots\cdot\cfrac{1}{2}\cdot\cfrac{\pi}{2},&\qquad m\text{为正偶数,}\\ \cfrac{m-1}{m}\cdot\cfrac{m-3}{m-2}\cdot\cdots\cdot\cfrac{2}{3},&\qquad m\text{为大于1的正奇数,} \end{cases}\\&=\begin{cases}\cfrac{1\cdot3\cdot5\cdot\cdots\cdot (m-1)}{2\cdot4\cdot6\cdot\cdots\cdot m)}\cdot\cfrac{\pi}{2},&\qquad m\text{为正偶数,}\\ \cfrac{2\cdot4\cdot6\cdot\cdots\cdot(m-1)}{1\cdot3\cdot5\cdot\cdots\cdot m},&\qquad m\text{为大于1的奇数.}\end{cases}\end{aligned}

附二  三角函数公式

  1. tan α cot α = 1 , \tan\alpha\cot\alpha=1,
  2. sin α csc α = 1 , \sin\alpha\csc\alpha=1,
  3. cos α sec α = 1 , \cos\alpha\sec\alpha=1,
  4. tan α = sin α cos α , \tan\alpha=\cfrac{\sin\alpha}{\cos\alpha},
  5. cot α = cos α sin α , \cot\alpha=\cfrac{\cos\alpha}{\sin\alpha},
  6. sin 2 α + cos 2 α = 1 , \sin^2\alpha+\cos^2\alpha=1,
  7. 1 + tan 2 α = sec 2 α , 1+\tan^2\alpha=\sec^2\alpha,
  8. 1 + cot 2 α = csc 2 α , 1+\cot^2\alpha=\csc^2\alpha,
  9. tan ( α + β ) = tan α + tan β 1 tan α tan β , \tan(\alpha+\beta)=\cfrac{\tan\alpha+\tan\beta}{1-\tan\alpha\tan\beta},
  10. tan ( α β ) = tan α tan β 1 + tan α tan β , \tan(\alpha-\beta)=\cfrac{\tan\alpha-\tan\beta}{1+\tan\alpha\tan\beta},
  11. cot ( α + β ) = cot α cot β 1 cot α + cot β , \cot(\alpha+\beta)=\cfrac{\cot\alpha\cot\beta-1}{\cot\alpha+\cot\beta},
  12. cot ( α β ) = cot α cot β + 1 cot α cot β , \cot(\alpha-\beta)=\cfrac{\cot\alpha\cot\beta+1}{\cot\alpha-\cot\beta},
  13. sin 2 α = 2 sin α cos α , \sin2\alpha=2\sin\alpha\cos\alpha,
  14. cos 2 α = cos 2 α sin 2 α = 2 cos 2 α 1 = 1 2 sin 2 α , \cos2\alpha=\cos^2\alpha-\sin^2\alpha=2\cos^2\alpha-1=1-2\sin^2\alpha,
  15. tan 2 α = 2 tan α 1 tan 2 α , \tan2\alpha=\cfrac{2\tan\alpha}{1-\tan^2\alpha},
  16. sin 3 α = 3 sin α 4 sin 3 α , \sin3\alpha=3\sin\alpha-4\sin^3\alpha,
  17. cos 3 α = 4 cos 3 α 3 cos α , \cos3\alpha=4\cos^3\alpha-3\cos\alpha,
  18. sin α = 2 tan α 2 1 + tan 2 α 2 , \sin\alpha=\cfrac{2\tan\cfrac{\alpha}{2}}{1+\tan^2\cfrac{\alpha}{2}},
  19. cos α = 1 tan 2 α 2 1 + tan 2 α 2 \cos\alpha=\cfrac{1-\tan^2\cfrac{\alpha}{2}}{1+\tan^2\cfrac{\alpha}{2}}
  20. sin α sin β = 1 2 [ cos ( α β ) cos ( α + β ) ] , \sin\alpha\sin\beta=\cfrac{1}{2}[\cos(\alpha-\beta)-\cos(\alpha+\beta)],
  21. cos α cos β = 1 2 [ cos ( α + β ) + cos ( α β ) ] , \cos\alpha\cos\beta=\cfrac{1}{2}[\cos(\alpha+\beta)+\cos(\alpha-\beta)],
  22. sin α cos β = 1 2 [ sin ( α + β ) + sin ( α β ) ] , \sin\alpha\cos\beta=\cfrac{1}{2}[\sin(\alpha+\beta)+\sin(\alpha-\beta)],
  23. cos α sin β = 1 2 [ sin ( α + β ) sin ( α β ) ] , \cos\alpha\sin\beta=\cfrac{1}{2}[\sin(\alpha+\beta)-\sin(\alpha-\beta)],
  24. sin α + sin β = 2 sin ( α + β 2 ) cos ( α β 2 ) , \sin\alpha+\sin\beta=2\sin\left(\cfrac{\alpha+\beta}{2}\right)\cos\left(\cfrac{\alpha-\beta}{2}\right),
  25. sin α sin β = 2 cos ( α + β 2 ) sin ( α β 2 ) , \sin\alpha-\sin\beta=2\cos\left(\cfrac{\alpha+\beta}{2}\right)\sin\left(\cfrac{\alpha-\beta}{2}\right),
  26. cos α + cos β = 2 cos ( α + β 2 ) cos ( α β 2 ) , \cos\alpha+\cos\beta=2\cos\left(\cfrac{\alpha+\beta}{2}\right)\cos\left(\cfrac{\alpha-\beta}{2}\right),
  27. cos α cos β = 2 sin ( α + β 2 ) sin ( α β 2 ) , \cos\alpha-\cos\beta=-2\sin\left(\cfrac{\alpha+\beta}{2}\right)\sin\left(\cfrac{\alpha-\beta}{2}\right),
  28. 0 π 2 f ( sin x ) d x = 0 π 2 f ( cos x ) d x , \displaystyle\int^{\frac{\pi}{2}}_0f(\sin x)\mathrm{d}x=\displaystyle\int^{\frac{\pi}{2}}_0f(\cos x)\mathrm{d}x,
  29. 0 π x f ( sin x ) d x = π 2 0 π f ( sin x ) d x , \displaystyle\int^{\pi}_0xf(\sin x)\mathrm{d}x=\cfrac{\pi}{2}\displaystyle\int^{\pi}_0f(\sin x)\mathrm{d}x,
  30. ( a b f ( x ) g ( x ) d x ) 2 a b f 2 ( x ) d x a b g 2 ( x ) d x , \left(\displaystyle\int^b_af(x)g(x)\mathrm{d}x\right)^2\leqslant\displaystyle\int^b_af^2(x)\mathrm{d}x\cdot\displaystyle\int^b_ag^2(x)\mathrm{d}x, f ( x ) f(x) g ( x ) g(x) 在区间 [ a , b ] [a,b] 上均连续,柯西-施瓦茨不等式)
  31. ( a b [ f ( x ) + g ( x ) ] 2 d x ) 1 2 ( a b f 2 ( x ) d x ) 1 2 + ( a b g 2 ( x ) d x ) 1 2 , \left(\displaystyle\int^b_a[f(x)+g(x)]^2\mathrm{d}x\right)^{\cfrac{1}{2}}\leqslant\left(\displaystyle\int^b_af^2(x)\mathrm{d}x\right)^{\cfrac{1}{2}}+\left(\displaystyle\int^b_ag^2(x)\mathrm{d}x\right)^{\cfrac{1}{2}}, f ( x ) f(x) g ( x ) g(x) 在区间 [ a , b ] [a,b] 上均连续,闵可夫斯基不等式)
  32. e i x = cos x + i sin x . e^{ix}=\cos x+i\sin x. (欧拉公式)

附三   Γ \Gamma 函数及其性质

  1. Γ ( s ) = 0 + e x x s 1 d x ( s > 0 ) , \Gamma(s)=\displaystyle\int^{+\infty}_0e^{-x}x^{s-1}\mathrm{d}x\qquad(s>0),
  2. Γ ( s + 1 ) = s Γ ( s ) ( s > 0 ) , \Gamma(s+1)=s\Gamma(s)\qquad(s>0),
  3. lim s 0 + Γ ( s ) + , \lim\limits_{s\to0^+}\Gamma(s)\to+\infty,
  4. Γ ( s ) Γ ( 1 s ) = π sin π s ( 0 < s < 1 ) , \Gamma(s)\Gamma(1-s)=\cfrac{\pi}{\sin\pi s}\qquad(0<s<1),
  5. Γ ( 1 2 ) = π . \Gamma\left(\cfrac{1}{2}\right)=\sqrt{\pi}.

附四  定积分和导数在几何上的应用

  1. 曲率: K = y ( 1 + y 2 ) 3 2 ; K=\cfrac{|y''|}{(1+y'^2)^{\frac{3}{2}}};
  2. 曲率半径: ρ = 1 K = ( 1 + y 2 ) 3 2 y ; \rho=\cfrac{1}{K}=\cfrac{(1+y'^2)^{\frac{3}{2}}}{|y''|};
  3. 曲线 y = f ( x ) ( f ( x ) 0 ) y=f(x)(f(x)\geqslant0) 及直线 x = a , x = b ( a < b ) x=a,x=b(a<b) x x 轴所围成的曲边梯形面积 A A A = a b f ( x ) d x ; A=\displaystyle\int^b_af(x)\mathrm{d}x;
  4. 极坐标系下曲线 ρ = ρ ( θ ) ( ρ ( θ ) 0 ) \rho=\rho(\theta)(\rho(\theta)\geqslant0) 及射线 θ = α , θ = β ( 0 < β α 2 π ) \theta=\alpha,\theta=\beta(0<\beta-\alpha\leqslant2\pi) 曲边扇形的面积 A A A = 1 2 α β [ ρ ( θ ) ] 2 d θ ; A=\cfrac{1}{2}\displaystyle\int^\beta_\alpha[\rho(\theta)]^2\mathrm{d}\theta;
  5. 连续曲线 y = f ( x ) y=f(x) 、直线 x = a x=a x = b x=b x x 轴所围成的曲边梯形绕轴转一周形成的旋转体体积 V V V = π a b [ f ( x ) ] 2 d x V=\pi\displaystyle\int^b_a[f(x)]^2\mathrm{d}x
  6. 设为垂直于定轴轴的截面面积函数为 A ( x ) A(x) ,则该立方体在区间 [ a , b ] [a,b] 之间的体积 V V V = a b A ( x ) d x ; V=\displaystyle\int^b_aA(x)\mathrm{d}x;
  7. 曲线弧长 s s s = a b 1 + y 2 d x ; s=\displaystyle\int^b_a\sqrt{1+y'^2}\mathrm{d}x;
  8. 参数方程 { x = φ ( t ) , y = ψ ( t ) ( α t β ) \begin{cases}x=\varphi(t),\\y=\psi(t)\end{cases}\quad(\alpha\leqslant t\leqslant\beta) 的曲线弧长 s s s = α β φ 2 ( t ) + ψ 2 ( t ) d t ; s=\displaystyle\int^\beta_\alpha\sqrt{\varphi'^2(t)+\psi^2(t)}\mathrm{d}t;
  9. 极坐标系下曲线 ρ = ρ ( θ ) ( α θ β ) \rho=\rho(\theta)\quad(\alpha\leqslant\theta\leqslant\beta) 的曲线弧长 s s s = α β ρ 2 ( θ ) + ρ 2 ( θ ) d θ . s=\displaystyle\int^\beta_\alpha\sqrt{\rho^2(\theta)+\rho'^2(\theta)}\mathrm{d}\theta.

未完待续。。。

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