# Search results

1. ### Three-phase transformer DC-resistances

Homework Statement Three-phase transformer, 20/0.5 kV, dyn11. Not connected to the grid. DC-resistance between two primary windings is measured to be 80 ohm. What is the DC-resistance of ONE primary coil Homework Equations The Attempt at a Solution I thought I could just...
2. ### Injection and surjection

Homework Statement Are the given functions injective? Surjective? a) seq: N -> Lists[N] b) f: Lists[A] -> P(A), f(x)=(<x1,x2,...,xn>)={x1,x2,...,xn} Homework Equations The Attempt at a Solution a) Ok so the domain contains a sequence of natural numbers. and the range contains a list...
3. ### Truth table and proving a tautology

Homework Statement I'm supposed to prove that this statement is a tautology (with truth table): (p -> ((p OR q) AND ~q)) = (~p OR ~q) AND p Homework Equations The Attempt at a Solution p | q | ~p | ~q | p OR q | (p OR q) AND ~q | p -> ((p OR q) AND ~q) | (~p OR ~q) | (~p OR...
4. ### Hasse diagram of a POSET

Ok I dont understand one thing...We ahd this example in school We have poset < {1,2,5,7,10,14,35,70}, | > | meas factor, for example a|b means b=ka, where k=integer and we got this Hasse diagram 70 / | \ 10 14 35 | X X | 2 5 7 \ | / 1 X means...
5. ### Finding Equivalence Class

Homework Statement Find the equivalence class  for the following equivalence relations: a) R: Z <-> Z, where xRy, iff |x| = |y| b) T: N <-> N, where xTy, iff xmod4 = ymod4 N means natural numbers etc...there wasnt the correct symbols in the latex reference Homework Equations ?? The...