```
from sympy import Symbol, Derivative, cos
import math
pi= math.pi
t= Symbol('t')
function_t = 2*cos(2*math.pi*t)*2.718**(-(math.pi*t)/2)
f1 = (function_t.doit().subs({t:1.5}))
print("When t=1.5,", f1)
```

I can't find a way to calculate cos in degrees in this function.