drawing a sine function in a r plot

Question

I would like to draw a simple sin and such a function

in a R plot.

I am using this code:

plot(sin, 0,  2*pi)
curve((4sin+(1/3)sin(3x))/pi, xlim = c(0, 2*pi), n = 1001, col = "blue", add = TRUE)

but I get this error:

Error: unexpected symbol in "curve((4sin"

What should I do to solve this problem?

Answer 1

You don't like the * symbol?

plot(sin, 0,  2*pi)
curve(4*(sin(x)+(1/3)*sin(3*x))/pi, xlim = c(0, 2*pi), n = 1001, col = "blue", add = TRUE)