basic trigonometric formulas written in black ink. of mathematical formulas

formula educational learning definition science hand teach single handwriting student typography mathematic study school element knowledge isolated equation graphic maths mathematics mathematical math lesson graph function class classroom design education calculus black algebra theory simple teaching learn geometric handwritten algebraic parabola elementary equations teachers numerical symbols variable real root coefficients quadratic solution solving higher text sin ratios tan cosine abstract angle scientific identities cotangent cos functions cosines trigonometric sine basic tangent trigonometry handdrawn drawing doodle calligraphy brush