Weird logic-design exam questions

  • #1

Homework Statement



Here are three problems from an exam and i'm not sure i understand the wording... almost like we're supposed to get these wrong.

4. The Boolean expression of the OR between minterm 6 and minterm 7 using variables ABC (A being the MSB and C being the LSB) is
{(A)} AB
(B) AC
(C) BC
(D) A+B
(E) A+C

6. The Boolean expression of the AND between minterm 6 and minterm 7 using variables ABC (A being the MSB and C being the LSB) is
{(A)} 0
(B) 1
(C) A
(D) A'
(E) B

15. The Boolean expression of the OR between maxterm 6 and maxterm 7 using variables ABC (A being the MSB and C being the LSB) is
(A) 0
{(B)} 1
(C) A
(D) A'
(E) B

Correct answers are marked.

The Attempt at a Solution



I did a k map and got AB as the sop for minterm 6 and minterm 7, and (A' + B') for the pos between maxterm 6 and 7, and AB looks like the answer for 4.

My problem is i have no idea what the questions are asking for,...well that and the TA didn't respond to my email :tongue:
 

Answers and Replies

  • #2
Well i checked with some software and my results for pos and sop are correct...

Owell, got my energy drinks so i'm gonna go study lol
 
  • #3
Ok i think i found a pattern that works atleast with these problems... correct me if i'm wrong :rofl:


For the Boolean expression of the OR between minterm 6 and minterm 7
They asked for the OR at minterms, do standard sop with k map = answer = AB

For the Boolean expression of the AND between maxterms 6 and maxterm 7
They asked for the AND at minterms, do standard pos with k map = answer = A'+B'

For the Boolean expression of the AND between minterm 6 and minterm 7
They asked for the AND at minterms, ...so convert the problem to equilivant maxterm form... which is 0's everywhere except at 6 and 7. I got a pos of (A+B)...and you see the "+"... that means, no their is not AND between them... so 0

For the Boolean expression of the OR between maxterm 6 and maxterm 7
They asked for the OR between maxterms...convert the problem to equilivant minterm form... which is 1's everywhere except 6 and 7. i got a sop of A'+B'...and you see the "+"...that means yes their is a OR between them, so 1

So yea that's the best guess i can ever do and it should work atleast some of the time :P

p.s. i had my exam and those questions weren't in the second exam... my teacher gave me a trashy homework grade though...like 2/21 despite the DAYS! i spent to make sure the hw was very correct, maybe he just checks the last one lol where i was a little iffy :P.... DON"T CARE... i'll pass the exams and say good bye (nah i'd say something i probably can't say in these forums) to the evil teacher :P
 

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