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SO I know that a tangent line is a line that touches a curve at one point, and a secant line is a line that touches a curve at TWO points, but what do tangent and secant lines have to do with tangent (tan(x)) and secant (sec(x)) functions?

Blue
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The_Animator
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1 Answers1

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The names are indeed what they sound like. This image says it all:

enter image description here

(found at https://www.mathematicalway.com/mathematics/trigonometry/tangent/).

FYI, "tangent" and "secant" come from Latin participles mean "touching" and "cutting", so the tangent line $DE$ glances off the circle whereas the secant line $AE$ cuts across it.

MPW
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