Question

Am I correct?
What is the assumption needed to begin an indirect proof of the following statement?

“Cows do not have horns.”

Bulls do not have horns.

Bulls have horns.

Cows do not have horns.

Cows have horns.

*this is considered math*

Answer 1

i think the answer is "Bulls have horns."

Answer 2

Cows have horns

Answer 3

That's close. You're trying to prove "Cows do not have horns". So you assume it is not true. How would you phrase it if it were not true?

Answer 4

@myko, please read the Code of Conduct. It is against the rules to post full answers. Thank you.

Answer 5

yw

Answer 6

lol, maths sure changed a lot

Answer 7

so @Limitless it is asking for the opposite?

Answer 8

Yes. The opposite of the statement "Cows do not have horns".

Answer 9

By the way, this is considered math because it illustrates the principle of proof by contradiction.

Answer 10

@samitheman99 its actually considered geometry no joke
@Limitless how so? that doesnt make sense if you think about the words "indirect proof" i would think it would be proving that statement by using another example

Answer 11

It's called "indirect proof" because you are proving it without explicitly proving it. You are proving it in a roundabout way. Hence, "indirect proof".

Answer 12

oh okay now i understand. :) thank you.

Answer 13

@LivForMusic & isn't geometry part of maths

Steps for Using Indirect Proofs
Step 1 Assume the opposite of the conclusion (or prove statement).
Step 2 Reason logically to show the assumption leads to a contradiction of a known fact.

Be sure to explain your whys!
Step 3 Conclude the assumption is false, which in turn proves the conclusion is true.

so "Cows have horns

Answer 14

np :)

Answer 15

Wait, @Calcmathlete, you assume the oppposite of the statement.

Answer 16

You don't assume the statement itself.

Answer 17

Oh yeah. Sorry. I had a brief brain fart.

Answer 18

It's cool.

@LivForMusic, what do you think the answer is?

Answer 19

@Limitless and @Calcmathlete so you minf helping with my next question that is similar. and i think the asnwer to this one is "cows have horns*

Answer 20

Correct. Good job.