please help me here:

we have a function:

f(x):=arctan(tan(x)*tan(x))

now let us look at the even derivative of this function at x = Pi/2. that is:

f^2(Pi/2) = -2

f^4(Pi/2) = -16

f^16(Pi/2) = -32

f^8(Pi/2) = 18944

f^10(Pi/2)= 1904128

is there a pattern in these numbers?

thanks

please help me here:

how can i integrate, say for example f(x) = cos(x), n times. means. how to find?

int(...int(int(int(cos(x),x),x),x)..,x)

thanks