First learn the structure. Learn the positions of the six trigonometry functions. First comes the function, underneath it comes the function. Then in the next column comes the function, underneath it comes the function. And in the last column comes the function and underneath it comes the function. Learning this position is important and just […]

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# High School Trigonometry

## The Trigonometric Ratio Hexagon

I found a book this morning containing a hexagonal figure of trigonometric ratios. It reminded me of the mnemonics I created when I was still in high school in order to remember the formulas during exams. Unlike in other countries, we were not allowed to have formula sheets during exams, so we have to memorize […]

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## The Proof of the Tangent Half-Angle Formula

In this post, we prove the following trigonometric identity: . Proof Consider a semi-circle with “center” and diameter and radius equal to 1 unit as shown below. If we let , then by the Inscribed Angle Theorem, . Draw perpendicular to as shown in the second figure. We can compute for the sine and cosine […]

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