ci | ci | cin

The most common form of cosine integral is Ci(x) | = | - integral_x^∞ (cos t d t)/t | = | γ + ln x + integral_0^x (cos t - 1)/t d t | = | 1/2[Ei(i x) + Ei(-i x)] | = | -1/2[E_1(i x) + E_1(-i x)], where Ei(x) is the exponential integral, E_n(x) is the E_n-function, and γ is the Euler-Mascheroni constant. Ci(x) is returned by the Wolfram Language command CosIntegral[x], and is also commonly denoted ci(x).

chi | damped exponential cosine integral | Nielsen's spiral | Shi | sine integral