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numbers and algebraic expressions
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polynomials
rational function
exponential function
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trigonometry
plane geometry
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combinatorics
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elements of statistics
kropki game

A rational function is a function of the form y = w(x) / p(x). w(x), p(x) -- polynomials. Examples: y = x^2+3 / x^2-3x+1, y = x+5 / x-2, y = x^3+x^2-1 / 5x^2+4. The domain of rational function find search roots (zeros) of a denominator. Examples. y = 5 / x-2, for x = 2 the denominator equal 0. D = R \ 2, all the real numbers except 2. y = 2x+4 / x^2-9, for x = 3 or x = -3 the denominator equal 0. D = R \ {-3,3}, all the real numbers except -3 and 3.