## Welcome to H3 Maths

Blog Support for Growing Mathematicians

## Posts tagged with trigonometry

### An ancient tablet that demonstrates undoubted genius

August25

For nearly 100 years, the mysterious tablet above (no, it’s not an iPad) has been referred to as Plimpton 322. It was first discovered in Iraq in the early 1900s by Edgar Banks, the American archaeologist on which the character Indiana Jones is thought to have been largely based. Now researchers from the University of […]

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### Trig Ratios Unplugged

May31

Sine, Cosine and Tangent are the three main trigonometric or Trig Ratios. Before we look at these in more detail, where did these strange terms come from? Trigonometric functions were studied by Hipparchus of Nicaea (180–125 BC), Ptolemy of Egypt (90–165 AD), Aryabhata (476–550), Varahamihira, Brahmagupta, Ulugh Beg and others (14th century). The word “sine” […]

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### Sine Method used to measure tallest tree

January23

Scientists recently measured the tallest tree in New Zealand at just over 81 metres. How did they do this? Using lasers and the Sine method – that is, the Sine of the angle formed by the lasers gave the height/hypotenuse. Read more here. (Note: This image is not of the tallest tree but gives some […]

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### The Art of Rectangular Pyramids

January15

Ah…The Louvre – perhaps the world’s most famous museum and an iconic, classical building which is noted for its modernistic entry which uses pyramids to contrast its surroundings. (H3 was taken aback by the beauty of this entry and the way in which it differed so much to the style of the French buildings and […]

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### Angles of Depression and Elevation

September13

Angles of Depression and Angles of Elevation both relate to the view from a horizontal line. When someone is depressed they tend to look down and the same is true for an angle of depression – it is an angle looking down from an imaginary horizontal line. In the sketch below, imagine someone in the […]

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### Touch Mathematics – cool curves

November2

Click here for the simpler Unit Circle of Sine

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### Go West Young Man!

May31

Yes, the cry of the early USA settlers was “Go West Young Man”. This exciting period of exploration led to large numbers of people travelling out to Oregon in the far west (read some interesting Trail Facts here). They faced incredible difficulties and many challenges, not only on the journey but also in settling into […]

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#### Post Support

NCEA Level 2 Algebra Problem. Using the information given, the shaded area = 9, that is:
y(y-8) = 9 –> y.y – 8y – 9 =0
–> (y-9)(y+1) = 0, therefore y = 9 (can’t have a distance of – 1 for the other solution for y)
Using the top and bottom of the rectangle,
x = (y-8)(y+2) = (9-8)(9+2) = 11
but, the left side = (x-4) = 11-4 = 7, but rhs = y+? = 9+?, which is greater than the value of the opp. side??
[I think that the left had side was a mistake and should have read (x+4)?]