Can someone help me with this problem, please? :(
It's computer architecture, and I've been stuck with it for the longest of time. Thanks in advance!

its been a long time since i messed with any boolean logic expressions but I'll try to help; i wasn't familiar with the notation that uses the bar over the top of each letter to indicate a negative or false expression, but if you convert it to a conventional expression (using ~ to indicate negation):

~(~a + ~b + ~cd~e) + ~(~bc~d)

NOT(NOTa AND NOTb AND NOTc AND d AND NOTe) AND NOT(NOTb AND c AND NOTd)

you may want to draw a map or truth tables first

http://dept-info.labri.u-bordeaux.fr/~strandh/Teaching/AMP/Common/Strandh-Tutorial/gates.html
http://cnx.rice.edu/content/m13240/latest/
http://www.gamezero.com/team-0/articles/math_magic/micro/boolean.html

i dont remember enough to tell if you can reduce it further, (for example ~(~a AND ~b) = a OR b ) but I really dont know what your teacher is looking for...

AHHH!! My savior! *bows down to thee* LOL.
Let's see... this is what I have written down... is it in "simplest form," though?
Like, is this the least number of gates that I can use? Or can I use even LESS? (I can only use AND, OR, and INVERTER). I used 14, I believe.

And I prefer to use the bar to indicate an inverse because it takes up less space when writing, LOL. The '~' symbol takes up the space of a character, and I am limited to an 8x11" paper, hehe. :D

Oh, and I also need assistance in one more question, LOL. :blush:
Design:
Use truth tables, SOP expression, simplify and implement.
A, B, C, & D are inputs of a counter. Z is the output and is to be High for counts of 0,1,2,3,5,7,11, and 15. Designt the circuit.

I've made the truth table, created the SOP expression... but I dont know how to simplify this expression. It's soooo long, LOL:

Z = ~A~B~C~D + ~A~B~CD + ~A~BC~D + ~A~BCD + ~AB~CD + ~ABCD + A~BCD +ABCD

im gonna say that that is beyond what I can remember how to simplify, but it looks like you should be able to simplify it

maybe this can help:

Boolean rules for simplification http://www.allaboutcircuits.com/vol_4/chpt_7/5.html

Circuit simplification examples http://www.allaboutcircuits.com/vol_4/chpt_7/6.html

Thanks for the sites, Rob. :)
I've given up on trying to simplify it, though, haha. I've spent the last five days preparing for my computer science finals. I think I need to rest before I drop dead! :lol:

BTW, I was wondering, do/did you major in computer science. And if you have, what courses do you take or have taken?

Comp sci is currently my major - has been for two years - but I'm thinking about switching 'cause it's driving me crazy. Too many logical-stuff, LOL. I've taken/am taking: A+ Certification, Database Management w/ Access, Java, VB.Net, PHP, HTML, DDL, SQL, Networking, computer architecture, blah blah.

Just curious. ;)

i did Architecture then Math/Computing Science - this was many years ago though :)

i remember they made me take philosphy and other weird, seemingly-unrelated courses, and I always had problems getting into classes because they were too full, I had to take some prerequisite courses after i finished the courses that required them :lol:

hang in there, its supposed to be hard, otherwise everyone would be doing it :)

Of all things - philosophy? LOL. Sometimes I wonder if schools really know what they're doing. :lol:

I'm still a senior in High School [majoring in college Computer Science], so I'll be graduating this June. Given that, I have the option of changing my major and starting 'fresh' in college, and still not be behind the rest of the freshman class.

But, if I do decide to change my major, I would have "wasted" two years, you know? :confused:

On the other hand, I really despise computer science. It's arduous. :(