
 zeef
 Super Member
Proof
Hi,
I really need help seeing if I answered the following correct:
I'll give you an assumption, and ask you to provide proof for the assumption. If there is no proof for the assumption, the answer is "unfounded."
I choose A
1. If I have two coplanar lines, I must have a plane.
Aunfounded BDefinition of a point CDefinition of a plane DGiven E Definition of a line F Definition of radius
Last edited by zeef (20121212 23:41:33)
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
 bob bundy
 Moderator
Re: Proof
hi zeef,
I think this can be proved. Isn't a plane defined by 3 (noncolinear ) points?
How could you find 3 such points on those two lines?
But I don't understand how you can prove that with just a letter. Have you got any examples of this sort of thing?
Bob
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
Re: Proof
A is correct.
The statement isn't even true. Two lines that are actually the same line do not define a single plane, but are coplanar.
The limit operator is just an excuse for doing something you know you can't. “It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman “Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
 zeef
 Super Member
Re: Proof
I answered A and it was incorrect .
Yeah this lesson is confusing but I did answer 14 correctly like this one : (F ) was correct
6. In the figure above, line segment MC is equal to imaginary line segment MI.
A Given Bunfounded CDefinition of supplementary angles D1267200 inches E Definition of an octagon F Definition of a circle: all points are equidistant from the center
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
 zeef
 Super Member
Re: Proof
I have to use the information I know to proof the statement correct
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
 bob bundy
 Moderator
Re: Proof
stefy wrote:Two lines that are actually the same line do not define a single plane, but are coplanar.
I did consider this, but rejected this interpretation on the grounds that 'two lines' should mean exactly two distinct lines not one line counted twice.
That's the trouble with using English to make mathematical statements. It sometimes isn't precise enough.
As zeef has had A marked wrong, I think we have further evidence that the questioner was thinking that way too.
So let's assume the lines are either (i) distinct and parallel or (ii) they cross at a point
So we either have 4 distinct points or at least 3.
What do we need to define a plane?
Bob
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
 zeef
 Super Member
Re: Proof
Hi,
According to my online courses A plane is defined by any of the following:
three points not lying on a line a line and a point not lying on the line two lines which intersect in a single point or are parallel
So I think C would be a correct answer
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
 bob bundy
 Moderator
Re: Proof
Yes, C sounds good. But I thought you had to supply the proof as well. Maybe not.
Bob
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
 zeef
 Super Member
Re: Proof
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
 bob bundy
 Moderator
Re: Proof
6/20 eeekkk!
Oh hang on. 6 wrong. Oh that's not so bad. 70% is a good score.
But we'll get them sorted. Don't worry.
I need to see the diagram for this one.
bob
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
 zeef
 Super Member
Re: Proof
yup 14/ 20
The lesson uses the same chart for all the questions that use the chart
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
 bob bundy
 Moderator
Re: Proof
hi zeef,
Oh, that diagram. I remember that from another set of questions.
So EJ = JM ? They're not telling that; they're asking is it true?
Take a look at the diagram. Is J half way along EM ?
Bob
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
 zeef
 Super Member
Re: Proof
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
 zeef
 Super Member
Re: Proof
So B would be a good answer ?
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
 bob bundy
 Moderator
Re: Proof
Yes, that's what I would choose.
Bob
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
 zeef
 Super Member
Re: Proof
I choose E and it was incorrect
my new answer is D 14. If a central angle is 30 degrees, then the arc it defines is also 30 degrees.
A Given BDefinition of an inscribed angle Cunfounded DProperties of a central angle E Properties of an arc F Definition of radius
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
 bob bundy
 Moderator
Re: Proof
I see why you said E to start with. I would say that D and E are the same. But if E isn't acceptable, D seems good to me.
Bob
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
 zeef
 Super Member
Re: Proof
yeah I was stuck on which one to choose to. lol
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
 zeef
 Super Member
Re: Proof
E was incorrect I still don't see why O_o
16. If a radius bisects a chord, then the lengths of the parts of the radius on either side of the chord are equal.
A Given BDefinition of a chord Cunfounded DDefinition of supplementary angles E Definition of a bisector F Definition of radius
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
 bob bundy
 Moderator
Re: Proof
I think my diagrams will show you what to do here.
Bob
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
 zeef
 Super Member
Re: Proof
No the radius isn't cut into equal parts so that whole statement is incorrect So C would be a good answer
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
 bob bundy
 Moderator
Re: Proof
Yes. That's what I think.
Bob
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
 zeef
 Super Member
Re: Proof
2 more left
I answered C for both it was incorrect
19. The given points (4, 8), (4, 5), and (2, 6) make a right triangle. A Distance Formula B Definition of a right triangle CDefinition of a triangle Dunfounded E Pythagorean Theorem F Definition of radius
20. The given points (2, 3), (7, 7), (2, 7), and (7, 2) make a square. A Definition of coordinate BPythagorean Theorem CDefinition of a square DDefinition of supplementary angles E Distance Formula F unfounded
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
 bob bundy
 Moderator
Re: Proof
hi
Did you try plotting the points? Have a look at my diagram.
I think you'll see what to do then.
Bob
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
 zeef
 Super Member
Re: Proof
No I didn't plot them probably why I got the question wrong the don't make a square or a right triangle So both (unfounded)
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
