Im very new to Mathematica, so spare me if there is a very trivial solution to this.

```
In(55):= c := cos (Pi*t)
d := sin (Pi*t)
c+d
Out(57)= cos(Pi*t)+Pi*sin(t)
```

Why does Mathematica output sin(Pi * t) as Pi*sin(t)? The cosine gets a correct output but the sine for some reason doesn’t.