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All Posts Tagged Tag: ‘pre-calculus’

How Do I Find the Focus of a Parabola?

This is a common question that we get from two audiences. It is most commonly asked by algebra students who want to calculate the point in the plane, when the equation of the parabola is given. More advanced students sometimes must prove this formula from the definition of the focus. We will handle this scenario second. We have also included …

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Finding the Directrix of a Parabola, Given its Vertex and Focus

Finding the directrix of a parabola, given its vertex and focus, when the equation of the parabola and its orientation are unknown.

Determining the Orientation of the Parabola Any time we are given only one or more of the following: Focus Vertex Axis of Symmetry Directrix and are asked to find one or more of the others, we must first determine the orientation of the parabola, if we are not already told what it is (as we usually are not). In the …

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Calculating Compound Interest

Compound Interest Problem

Problem – Pre-Calculus – How to Calculate Compound Interest on an Investment In this problem, we walk through a question on calculating compound interest. In the explanation video, we spend some time on on the compound interest formula, itself, and distinguish it from simple interest scenarios. Comparison with Simple Interest: Notice that at the end of the investment period, you …

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