# Boolean Algebra Help

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#### cat

Joined Sep 25, 2006
8
Hi guys,

I have a question that i can't find the answer to:

There's a given function: F=x+yz
Then i have to show that F+F'=1
I found that F'=x'y'+x'z'

therefore:

F+F'=x+yz+x'y'+x'z'
=yz+(xx')(xz')+x'y'
=yz+x'y'

i don't know how to go from here
Have i done something wrong.
cat

#### oldbird

Joined Sep 24, 2006
3
F+F'=x+yz+x'y'+x'z'
=x+yz+x'(y'+z')
=x+yz+x'(yz)'
=(x'(yz)')'+x'(yz)'
=1

#### Søren

Joined Sep 2, 2006
472
Hi,

[...] Then i have to show that F+F'=1
Oh Gee, aren't school teachers dull, dumb and delusional

Whatever the (Boolean) function is, F + /F will allways yeild "1" as it's an OR of something and its opposite - That's basic Boolean !

#### cat

Joined Sep 25, 2006
8
thanks sooooo much oldbird

hay soren, what you are saying is right but you know, poor students like us have to do the homeowrk that they give. otherwise we are screwed
thanks for the comment anyways
cat

#### mik3ca

Joined Feb 11, 2007
189
Show that F' + F = 1
LMAO

Have the teacher refer to the "OR" gate truth table, because in an OR gate, an input, along with the same input inverted equals 1.

#### Papabravo

Joined Feb 24, 2006
16,795
Søren;20671 said:
Hi,

Oh Gee, aren't school teachers dull, dumb and delusional

Whatever the (Boolean) function is, F + /F will allways yeild "1" as it's an OR of something and its opposite - That's basic Boolean !
Except that you missed the point of the exercise. If you're too ignorant to figure it out, then I'm cetainly not going to enlighten you.

#### Papabravo

Joined Feb 24, 2006
16,795
LMAO

Have the teacher refer to the "OR" gate truth table, because in an OR gate, an input, along with the same input inverted equals 1.
Two clowns in one day missed the point of the exercise. What's a poor student to do when faced with such boorishness.

#### Dave

Joined Nov 17, 2003
6,970
LMAO

Have the teacher refer to the "OR" gate truth table, because in an OR gate, an input, along with the same input inverted equals 1.
This is an old thread, please do not resurrect an old thread unless you are going to contribute something to the answer that may be of benefit to others.

Two clowns in one day missed the point of the exercise. What's a poor student to do when faced with such boorishness.
Do not refer to other members as "clowns" - you are free to make a point but please do it with some propriety.

This topic will now be closed and only reopened at the OPs request.

Dave

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