ref: b9ff09189979b272200d32668b4e42f292512dcd
dir: /posix/math.h/
float cosf(float); float sinf(float); float tanf(float); float atanf(float); float atan2f(float, float); float fabsf(float); float sqrtf(float); float acosf(float); float floorf(float); float ceilf(float); float fmodf(float, float);