HP 39GS hp 39gs_user's guide_English_E_HDPMG39AE13.pdf - Page 156

10x ,, ASIN ACOS Exponential (antilogarithm). Also accepts complex numbers. 10^value Example 10^3 returns 1000 Common logarithm. Also accepts complex numbers. LOG(value) Example LOG(100) returns 2 Sine, cosine, tangent. Inputs and outputs depend on the current angle format (Degrees, Radians, or Grads). SIN(value) COS(value) TAN(value) Example TAN(45) returns 1 (Degrees mode). Arc sine: sin-1x. Output range is from -90° to 90°, -π/2 to π/2, or -100 to 100 grads. Inputs and outputs depend on the current angle format. Also accepts complex numbers. ASIN(value) Example ASIN(1) returns 90 (Degrees mode). Arc cosine: cos-1x. Output range is from 0° to 180°, 0 to π, or 0 to 200 grads. Inputs and outputs depend on the current angle format. Also accepts complex numbers. Output will be complex for values outside the normal COS domain of -1 ≤ x ≤ 1 . ACOS(value) Example ACOS(1) returns 0 (Degrees mode). 13-4 Using mathematical functions