Cosecant, Secant & Cotangent Calculator

All reciprocal ratios at once.

How it is calculated

The angle is entered in degrees and converted to radians. The tool then computes csc θ = 1 ÷ sin θ, sec θ = 1 ÷ cos θ and cot θ = cos θ ÷ sin θ, each shown to 6 decimal places as a unitless ratio. Negative angles and angles above 360° work, because the functions repeat every 360° (390° gives the same values as 30°). Only the function that is truly undefined is blanked and shown as a dash: csc and cot when sin θ is practically zero (0°, 180° and their multiples), and sec when cos θ is practically zero (90°, 270°). The other values are still given, so at 90° you get csc = 1.000000, sec = — and cot = 0.000000. An empty box gives nothing.

Worked example

Take θ = 30°. sin 30° = 0.5 and cos 30° ≈ 0.866025. Taking reciprocals: csc 30° = 1 ÷ 0.5 = 2.000000, sec 30° = 1 ÷ 0.866025 ≈ 1.154701, and cot 30° = cos ÷ sin = 0.866025 ÷ 0.5 ≈ 1.732051. The tool prints exactly these three numbers. A useful check: cot 30° is also 1 ÷ tan 30° = 1 ÷ 0.577350, which gives 1.732051 again.

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Common mistakes

  • Confusing the reciprocal with the inverse function. sec θ is 1 ÷ cos θ, whereas arccos gives an angle; 1.154701 here is a ratio, not 30°.
  • Entering radians. 1.5708 is treated as 1.5708 degrees, not as a right angle.
  • Reading a dash as an error. At 0° and 180° cosecant and cotangent are undefined, and at 90° and 270° the secant is, so the tool shows a dash for exactly those and still gives the rest.
  • Pairing the wrong function with its base. Cosecant goes with sine and secant goes with cosine, which is easy to reverse because the names look the wrong way round.
  • Expecting values between −1 and 1. Secant and cosecant are never inside that range; their size is always 1 or more, while cotangent can be any number.

About this calculator

Cosecant, secant and cotangent are the three reciprocal trigonometric functions: csc(θ) = 1/sin(θ), sec(θ) = 1/cos(θ), and cot(θ) = 1/tan(θ) = cos(θ)/sin(θ). They carry the same information as sine, cosine and tangent but flip the ratio, which makes certain formulas — especially in calculus and integration tables — much cleaner to work with, and they are undefined exactly where their base function equals zero (csc and cot at 0°/180°, sec at 90°/270°).

Electrical engineers use secant and cosecant when working with impedance and phase-angle relationships in AC circuits, while cotangent shows up constantly in optics (Brewster's angle calculations), surveying, and in identities like 1 + cot²(θ) = csc²(θ) that simplify trigonometric equations. In calculus, the derivatives and integrals of sec and csc appear frequently enough — d/dx[tan x] = sec²x, for example — that having quick reciprocal values on hand speeds up checking work by hand.

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