Prove the Given Statement....3

  • MHB
  • Thread starter mathdad
  • Start date
In summary, the problem states that a circle with the equation x^2 + 2Ax + y^2 + 2By = C has two intercepts, a and b, and two y-intercepts, c and d. The goal is to prove that a•b + c•d = -2C. By using the product of the roots formula and plugging in the values, it can be shown that the equation holds true. Therefore, the statement has been proven.
  • #1
mathdad
1,283
1
Suppose that the circle x^2 + 2Ax + y^2 + 2By = C has two intercepts, a and b, and two y-intercepts, c and d.
Prove that a•b + c•d = -2C

How is this started?
 
Mathematics news on Phys.org
  • #2
Once you work the first two problems in this series, this one should be a walk in the park. :D
 
  • #3
I am stuck with the second problem in the series.
 
  • #4
RTCNTC said:
Suppose that the circle x^2 + 2Ax + y^2 + 2By = C has two intercepts, a and b, and two y-intercepts, c and d.
Prove that a•b + c•d = -2C

$$A=-\frac{a+b}{2}$$

and the point (a, 0) is on the circle. Plug and chug:

$$-ab=C$$

Get sneaky:

$$2ab=-2C$$

...and using the result from part 2:

$$2ab=ab+cd=-2C$$

QED
 
  • #5
Nicely done.
 
  • #6
If you use the product of the roots formula, you get:

\(\displaystyle ab+cd=-C-C=-2C\) :D
 
  • #7
Thank you, Mark. Thank you everyone.
 

FAQ: Prove the Given Statement....3

What does it mean to "prove" a statement?

To prove a statement means to provide evidence or logical arguments that support the truth or validity of the statement. In other words, it is demonstrating that the statement is true or can be accepted as true.

How do you prove a given statement?

To prove a given statement, you need to follow a logical and systematic approach. This typically involves breaking down the statement into smaller parts, using established mathematical or scientific principles, and providing evidence or reasoning to support each part. It may also involve conducting experiments or gathering data to support the statement.

Can a statement be proven wrong?

Yes, a statement can be proven wrong if it is found to be inconsistent with existing evidence or if there is a logical flaw in the reasoning used to support it. The process of disproving a statement is also an important part of the scientific method.

How do you know when a statement has been proven?

A statement is considered to be proven when there is sufficient evidence or reasoning to support its truth or validity. This evidence should be based on reliable and verifiable data, and the reasoning should follow established principles and logic. It is also important to consider alternative explanations or counterarguments when evaluating the validity of a statement.

Are there different types of proof for a statement?

Yes, there are different types of proof for a statement depending on the context and type of statement. In mathematics, a proof may involve using logical deductions and equations to show that a statement is true. In science, a proof may involve conducting experiments and analyzing data to support a hypothesis or theory. In other fields, such as philosophy or law, different types of reasoning and evidence may be used to support a statement.

Similar threads

Replies
3
Views
1K
Replies
16
Views
2K
Replies
4
Views
1K
Replies
3
Views
2K
Replies
1
Views
748
Replies
2
Views
1K
Replies
11
Views
6K
Back
Top