# Sin, cosine, tangent ratios

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Who invented these ratios?

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Um, no one really invented them. trigonometry has certain relationships between angles and lengths in a right angled triangles (there are obviously god knows how many other situations which involve sin cos and tan but right angled triangles are the simplest application that comes to mind).

sin = opp/hyp

Its just a ratio of lengths which are constant in a right angled triangle.

Sin Cos and Tan 'ratios' were determined not invented. They are mathematical functions which are used, not entities in their own right which were created. If your asking who specifically determined them then sorry, that escapes my memory at the moment. Anyone know? it wasnt Newton was it? His name comes to mind for some reason.

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trig functions are pretty much a core part of mathematics: you can't really get away from them. i don't think Newton invented the actual terms sine, cosine and tangent, but i think the names themselves were derived from the unit circle that can be drawn. i'm not exactly sure how they fit in though.

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basic trig must date back an extremely long time, arabic mathematics maybe? they invented most simple principles i believe.

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Originally posted by dave

trig functions are pretty much a core part of mathematics: you can't really get away from them. i don't think Newton invented the actual terms sine, cosine and tangent, but i think the names themselves were derived from the unit circle that can be drawn. i'm not exactly sure how they fit in though.

So the ratios were performed deductively, for an infinite amount of values? Until sufficient ratios & numbers were calculated?

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Originally posted by NSX

So the ratios were performed deductively, for an infinite amount of values? Until sufficient ratios & numbers were calculated?

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Originally posted by MrL_JaKiri

They said that noone invented the ratios...so I'm asking if someone, or a group of people sat down, and measured the figures of a unit circle according to different patterns of opposite / hypotoneuse, etc.

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Originally posted by NSX

They said that noone invented the ratios...so I'm asking if someone, or a group of people sat down, and measured the figures of a unit circle according to different patterns of opposite / hypotoneuse, etc.

You don't need to; you can get the trigonometric relationships without numbers, and you can then derive any value from the taylor series.

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Originally posted by MrL_JaKiri

you can then derive any value from the taylor series.

Right....

hehe

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