Read	Denoted
the inverse sine of x	arcsin x or sin-1x
the inverse cosine of x	arccos x or cos-1x
the inverse tangent of x	arctan x or tan-1x
the inverse cotangent of x	arccot x, or arcctg x or cot-1x
the inverse of secant of x	arcsec x or sec-1x
the inverse cosecant of x	arccsc x, or arccosec x or csc-1x

Since sin30° = 0.5, the inverse sine of 0.5 is 30°, that is, arcsin0.5 = 30°.