formulas
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Feynmann's Trick For Exponential Integrals
$$\int_0^{\infty} x^n e^{-tx} dx = \frac{n!}{t^{n+1}}$$
Finite and Infinite Geometric Sums
$$S_n = \frac{a(1-r^n)}{1-r}$$
Convolution
$$(f*g)(t)=\int_{-\infty}^{\infty} f(\tau)g(t-\tau)d\tau$$
Shockley Diode Model
$$I = I_S \cdot (e^{\frac{V_D}{nV_T}} - 1)$$
Schrodinger's Equation
$$\scriptsize i\hbar\frac{\partial}{\partial t}\Psi(x,t) = \left[-\frac{\hbar^2}{2m}\frac{\partial^2}{\partial x^2} + V(x,t)\right]\Psi(x,t)$$
L'Hopital's Rule
$$\lim_{x \to c} \frac{f(x)}{g(x)} = \lim_{x \to c} \frac{f'(x)}{g'(x)}$$
Lorentz Transformations
$$x' = \frac{x-vt}{\sqrt{1-v^2/c^2}}$$
Determinants of Matrices
$$\det(A)$$
Double Angle Trig Identities
$$\sin(2\theta) = 2 \cdot \sin(\theta) \cdot \cos(\theta)$$
Trig Angle Sum/Difference Identities
$$\scriptsize \sin(a \pm b) = \sin(a) \cos(b) \pm \cos(a) \sin(b)$$
Vector Projection
$$proj_{\vec{b}}(\vec{a})=\frac{\vec{a}\cdot\vec{b}}{\|\vec{b}\|^2}\vec{b}=(\vec{a}\cdot\hat{b})\hat{b}$$
Green's Theorem
$$\small \oint_C Pdx + Qdy = \iint_D \frac{\partial Q}{\partial x} - \frac{\partial P}{\partial y} dA$$
Hooke's Law (Modulus of Elasticity)
$$\frac{F}{A} = E\frac{\Delta L}{L}$$
Hooke's Law (Spring Constant)
$$F = -kx$$
Hyperbolic Functions
$$\sinh(x) = \frac{e^x - e^{-x}}{2}$$
Stokes' Theorem
$$\int_C \vec{F} \cdot d\vec{r} = \iint_S \nabla \times \vec{F} \cdot d\vec{S}$$
Cross Product
$$\vec{a} \times \vec{b} = \begin{vmatrix} \vec{i} & \vec{j} & \vec{k} \\ a_1 & a_2 & a_3 \\ b_1 & b_2 & b_3 \end{vmatrix}$$
Divergence Theorem
$$\iiint_V (\nabla \cdot \vec{F}) dV = \oiint_S (\vec{F} \cdot \hat{n}) dS$$
Dot Product
$$\vec{a} \cdot \vec{b} = \sum_{i=1}^n a_i b_i$$
Ampere's Law
$$\oint \vec{B} \cdot d\vec{l} = \mu_0 I$$
Gauss's Law
$$\oiint \vec{E} \cdot d\vec{A} = \frac{Q_{enc}}{\epsilon_0}$$
Cosine Law
$$c^2 = a^2 + b^2 - 2 \cdot a \cdot b \cdot \cos(\theta)$$
Definition of the Derivative
$$\frac{d}{dx}f(x) = \lim_{h\to 0}\frac{f(x+h)-f(x)}{h}$$
Pythagorean Trig Identities
$$\sin^2(x) + \cos^2(x) = 1$$
Cauchy's Integral Theorem
$$\oint_C f(z)dz = 0$$
Gravitational Potential Energy
$$U = mgh$$
Kinetic Energy
$$E_k = \frac{1}{2}mv^2$$
Laplace's Equation
$$\nabla^2 f = \nabla \cdot \nabla f = 0$$
Fundamental Theorem of Calculus
$$\int_a^b f(x) dx = F(b) - F(a)$$
Pythagorean Theorem
$$a^2 + b^2 = c^2$$