# Co-sine

## Definitions

• Chambers's Twentieth Century Dictionary
• n Co-sine kō′-sīn the sine of the complement of a given angle (whose co-sine it is).
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## Usage

### In literature:

We will gossip about sines and co-sines before we die.
"The Odd Women" by George Gissing
Define the terms sine, co-sine, tangent, and co-tangent.
"Scientific American Supplement, No. 561, October 2, 1886" by Various
Inventor of the terms co-sine, co-tangent, etc.
"A Brief Handbook of English Authors" by Oscar Fay Adams
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### In news:

Carole King was in a doo-wop group called the Co-Sines when she was a teenager.
Carole King, From Co-Sine To Chart Topper .
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### In science:

For D ≡ 1 (mod 4) it is also an algebraic integer when a and b as special values of (co)sine at rational angles. Z. (Note e.g. that 1 Observation (Quadratic Irrationalities). i) Let x be a quadratic integer such that |x| < 2 and |x| < 2.
When is the (co)sine of a rational angle equal to a rational number?
The zeroes found are indeed special values of (co)sine at rational angles.
When is the (co)sine of a rational angle equal to a rational number?
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