formulas
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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
$$a^2 + b^2 = c^2$$
Maclaurin Series for exp(x)
$$e^x = \sum_{n=0}^\infty \frac{x^n}{n!}$$
Momentum (Newtonian)
$$p = mv$$
Quadratic Formula
$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
Newton's 2nd Law
$$F = ma$$
Euler's Identity/Formula
$$e^{i\pi} = -1$$
Trig functions in terms of e
$$\small{\sin(x) = \frac{e^{ix} - e^{-ix}}{2i}, \cos(x) = \frac{e^{ix} + e^{-ix}}{2}}$$
Ideal Gas Law
$$PV = nRT$$