Shortcut Methods

Numerical of Indefinite Integral

  • Power Rule: xndx=xn+1n+1+C for any real number (n \neq -1).

  • Sum Rule: (f(x)+g(x))dx=f(x)dx+g(x)dx

  • Difference Rule: (f(x)g(x))dx=f(x)dxg(x)dx

  • Constant Multiple Rule: cf(x)dx=cf(x)dx

  • Substitution Rule: If (u = g(x)) is a differentiable function, then f(g(x))g(x)dx=f(u)du

  • Logarithmic rule: 1xdx=ln|x|+C,(x0)

  • Exponential Rule: exdx=ex+C

Numerical of Definite Integral

abf(x)dx=F(b)F(a),

where (F(x)) is an antiderivative of (f(x)) (i.e. (\frac{d}{dx}F(x) = f(x))).

Applications of Integral Calculus

  • Area under a curve: Area=abf(x)dx

  • Volume of a solid generated by revolving a region around an axis: Volume=abA(x)dx,

where (A(x)) is the area of the cross-section of the solid at (x).

  • Work done by a force: Work=abF(x)dx,

where (F(x)) is the force applied at the point (x).

  • Average value of a function: Averagevalue=1baabf(x)dx

  • Probability: Probability=abf(x)dx,

where (f(x)) is the probability density function of the random variable (X).