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making text look nice

Introduction

Following applet shows how you can make texts with equations look nice.
  • You don't want terms with coefficient 0 in it.
  • You don't want double signs.
  • You want a proper solution of an equation as an integer if so and if not you don't want a fraction with negative signs for both nominator and denominator.

How do you do this?

  • Equation of a function: Create: - a slider a from -4 to 4 with increment 1. - a slider b from -4 to 4 with increment 1. - a slider c from -4 to 4 with increment 1. - a function f(x) = a x² + b x + c - a function g(x) = Polynomial(a x² + b x + c) - Show the equations of f and g in a dynamic text and experiment with the sliders. You'll notice that the command Polynomial(< Funcion>) avoids 0 and 1 as coefficients.
  • Solving equations: Create: - a slider d from -5 to 5 with increment 2. - a slider e from -5 to 5 with increment 2. - a slider h from -4 to 4 with increment 1. How to show the solving of the equation dx + e = h nicely? Left you see the Textfield in a 'normal' way, which doesn't always look nice. Right we use some tricks to avoid double signs and to show a nice solution.
Image
  • first row: - Create a function ff(x) = Polynomial ( d x + e). - use ff in a dynamic text for the left side of the equation to prevent double signs.
  • second row: - Create a function fff(x) = Polynomial (dx) to avoid 1 as a coefficient. - Define a text signe = If(e < 0, "+", "") to use in the right side of the equation and add -e. If e = -3: signe will show a + sign, -e hasn't got a sign on its own, so the right side will show: -4 + 3. Change slider e to 3: signe will be blank and -e will be -3, so the right side will show: - 4 - 3.
  • third row: - Create a dynamic text with the command FractionText((h - e) / d). This command will show the solution in its most simple form: If the nominator is a multiple of the denominator the solution will be shown as an integer, if not as a fraction. If both nominator and denominator are negative, both signs will be ommitted.