Update recitation-session-2.md

- Remove type incorrect hint for uncurry2 (I don't think this hint helps understanding the question...)
- Rename f' to g in the curry2 description (someone asked why we are taking the derivative of f...)
- Swap the arguments of curry2/uncurry2, `(Double, Int)` is more convinient to give an example with `Math.pow`

recitation-sessions/recitation-session-2.md

@@ -40,20 +40,18 @@ _Hint_: What values should be returned by `repeated(x => x + 1, 0)` and `repeate
 
 ## Exercise 3.1
 
-Define the function `curry2`, that curries a two arguments function. That is, `curry2(f) = f'` such that `f(x, y) == (f'(x))(y)`
+Define the function `curry2`, that curries a two arguments function. That is, `curry2(f) = g` such that `f(x, y) == (g(x))(y)`
 
 ```scala
-def curry2(f: (Int, Double) => Boolean): Int => (Double => Boolean) = ???
+def curry2(f: (Double, Int) => Boolean): Double => (Int => Boolean) = ???
 ```
 
-_Hint_: what should `curry2((x, y) => x + y)(1.0)` return?
-
 ## Exercise 3.2
 
 Define the function `uncurry2`. It takes a curried function, and creates a two-argument function.
 
 ```scala
-def uncurry2(f: Int => Double => Boolean): (Int, Double) => Boolean = ???
+def uncurry2(f: Double => Int => Boolean): (Double, Int) => Boolean = ???
 ```
 
 ## Exercise 4.