Functions in stan/math/prim using apply_scalar_unary or apply_vector_unary

apply_x_unary

These are all the files in stan/math/prim/fun that reference apply_scalar_unity:

acosh.hpp
acos.hpp
approx.hpp
asinh.hpp
asin.hpp
atanh.hpp
atan.hpp
cbrt.hpp
ceil.hpp
cloglog.hpp
cosh.hpp
cos.hpp
digamma.hpp
division.hpp
erfc.hpp
erf.hpp
exp.hpp
fabs.hpp
floor.hpp
inv.hpp
lgamma.hpp
log.hpp
logit.hpp
meta.hpp
m.hpp
Phi.hpp
p.hpp
round.hpp
sinh.hpp
sin.hpp
sqrt.hpp
square.hpp
tanh.hpp
tan.hpp
tgamma.hpp
trigamma.hpp
trunc.hpp
unary.hpp

These things have apply_vector_unary:
acos.hpp
asin.hpp
atan.hpp
ceil.hpp
cloglog.hpp
cosh.hpp
cos.hpp
exp.hpp
fabs.hpp
floor.hpp
inv.hpp
log.hpp
logit.hpp
max.hpp
mean.hpp
meta.hpp
min.hpp
round.hpp
sinh.hpp
sin.hpp
softmax.hpp
sqrt.hpp
square.hpp
tanh.hpp
tan.hpp