#### Teg-Men

##### Junior Member level 2

I used REAL, PARAMETER :: PI = 3.14159265358979323846264338327950288419716939937510

statement and also this number that is obtained by Gregory–Leibniz series:

PI = 16*ATAN(1./5.) - 4*ATAN(1./239.)

I applied them into WRITE(*,*) TAN(PI*THETA/180) statement where Theta is input in degree

For 45 degree, both give me 1.00000

But for 90 degree they again both give -2.287733E+07

So, where is the problem, with PI? or Fortran?