exp(x) function compute the exponential value of a number or number vector, e^x.

> x <- 5
> exp(x)  # = e5
[1] 148.4132
> exp(2.3) # = e2.3
[1] 9.974182
> exp(-2) # = e-2
[1] 0.1353353

To get the value of the Euler's number (e):

> exp(1)
[1] 2.718282

> y <- rep(1:20)
> exp(y)

[,1] [,2] [,3] [,4] [,5]
[1,] 2.718282 20.08554 148.4132 1096.633 8103.084
[2,] 7.389056 54.59815 403.4288 2980.958 22026.466

^ operator calculates a raised to power b:

> 2^3

[1] 8

> 8 ^ (1/3)
[1] 2
> exp(log(8)/3)
[1] 2
> exp(log(32)/5)
[1] 2

expm1() function computes exp() minus 1:

> expm1(5) # = e5 -1 

[1] 147.4132

> expm1(rep(1:20))

[,1] [,2] [,3] [,4] [,5]
[1,] 1.718282 19.08554 147.4132 1095.633 8102.084
[2,] 6.389056 53.59815 402.4288 2979.958 22025.466

Let's plot the exponential value in the range of -4 ~ 10:

> x <- seq(-4, 10, by=0.1)
> plot(x,exp(x),typ="l",col="green")