I think you're thinking of the inverse cosine function arccosine. The reciprocal of the cosine function is known as the secant. I do not know if this is specifi

I think you're thinking of the inverse cosine function arccosine. The reciprocal of the cosine function is known as the secant. I do not know if this is specific to English speaking countries. However the Chinese version of wikipedia suggests it is: http://zh.wikipedia.org/zh/反三角函数 http://zh.wikipedia.org/zh/反三角函数