# Memory error mixing exact numbers and decimal ones

Hi,

I wonder why this code gives an error in Sage 7.5.1:

```
f(x)=3*sin(2*pi*(1.75-2*x))
if abs(f(0.7)) < 1e-12:
print 1
MemoryError: Not enough memory to calculate cyclotomic polynomial of 428914250225777
```

Checking whether a given expression is close to zero symbolically can be very challenging. Still, it does seem surprising that this would come in with something that seems simple ... as a workaround, try

`f(0.7).n()`

instead. (The`pi`

is not approximated otherwise, which is presumably what is leading to this problem.)