List of Topics

SfC Home > Arithmetic > Algebra >

 

Feedback Q&A on Algebra

by Ron Kurtus

Readers have sent in a total of 66 comments and questions on Algebra issues. They are listed according to date.

You can read them to further your understanding of the subject.



List of next 10 letters

Topic

Title

Country

General Why is derivative of e^x = e^x? Australia
 
General Antiderivative of sin(3x+1)dx Australia
 
Square Root Approximation Newton method very nice India
 
Fractals What is self-similarity and what is fractal? USA
 
General Find the perimeter of a triangle USA
 
General Trouble understanding math and science USA
 

Next 10

 




First 10 letters


Why is derivative of e^x = e^x?

Topic: General

Question

December 10, 2008

why does the Derivative of e^x is still e^x?
Why does the derivative of sinx=cosx?<

String - Australia

16927

Answer

e^x is one of the unusual expressions that equals its derivative. de^x/dx = e^x
A simple derivation can be seen at: http://math2.org/math/derivatives/more/e^x.htm, but it is difficult to understand.

Although you can prove sinx = cosx through the use of the derivative of a series, most sources say sinx = cosx by definition.

Typically, you simple have to memorize these relationships or use a reference table.

Back to top


Antiderivative of sin(3x+1)dx

Topic: General

Question

December 10, 2008

why does an antiderivative of sin(3x+1)dx=(-cos(3x+1)+C)/3
Why it has to be devided by 3?
Can you give a ful detail as many you can Please?

String - Australia

16928

Answer

The anti-derivative of sin(nx)dx = -[cos(nx)]/n
Thus sin(3x)dx = - [cos(3x)]/3

Also sin(a+b) = sin(a)cos(b) - cos(a)sin(b)

But I'm at a loss where they get (-cos(3x+1)+C)/3. I assume that C is some constant?

Sorry, that is the best I can do without knowing what your teacher was getting at.

Back to top


Newton method very nice

Topic: Square Root Approximation

Question

January 15, 2008

The method to calculate the square root for any number using newton method is very nice.

siva - India

15137

Answer

Thanks for the feedback. I'm glad you found the method useful.

Back to top


What is self-similarity and what is fractal?

Topic: Fractals

Question

October 20, 2007

What is self-similarity and what is fractal? I not sure I completely understand what the two are and what the difference is between them.

Denise - USA

14592

Answer

A fractal is a design or fragmented geometric shape that repeats the same design in smaller and smaller patterns. It is like taking a triangle and putting a smaller triangle on each side, and then putting even smaller triangle on each side of those triangles, and so on.

Self-similarity is a property of fractals, where an object is exactly or approximately similar to a part of itself,.

Back to top


Find the perimeter of a triangle

Topic: General

Question

March 6, 2007

How do I find the total length of the perimeter of a right triangle, when the angles are known and the length of one side is known.

Example: angles 90, 60, 30 adjacent side = 12 inches.

Dan - USA

13319

Answer

If, by the adjacent side you mean they hypotenuse of the triangle, you can find the length of the sides by using the sine of the angles.

The sine of 30° is 1/2 times 12 or 6 inches. That is the side opposite 30°. The sine of 60° is 0.866 time 12 = 10.39.

As a double-check, you can use Pythagorean Theory 12 squared = 6 squared + 10.39 squared. 144 = 36 + 108.

Back to top


Trouble understanding math and science

Topic: General

Question

January 31, 2004

How can I understand math and science?

Laura - USA

2196

Answer

Our lessons in Physical Science can help you understand that topic for your class. I also have Algebra lessons for you to use. Hopefully, your teachers will do a good job in helping you learn.

Back to top

Next 10


Summary

Hopefully, this reader feedback has helped provide information about Algebra issues.


Always do your best


Resources and references

Ron Kurtus' Credentials

Websites

Algebra Resources

Books

Top-rated books on Algebra


Questions and comments

Do you have any questions, comments, or opinions on this subject? If so, send an email with your feedback. I will try to get back to you as soon as possible.

Feel free to establish a link from your website to pages in this site.


Where are you now?

School for Champions

Algebra

Feedback Q&A on Algebra




Algebra topics

Basics

Terminolgy

Properties

Expressions

Exponents and roots

Equations

Quadratic equations

Also see



Let's make the world a better place

Be the best that you can be.

Use your knowledge and skills to help others succeed.

Don't be wasteful; protect our environment.

You CAN influence the world.





Live Your Life as a Champion:

Take care of your health

Seek knowledge and gain skills

Do excellent work

Be valuable to others

Have utmost character

Be a Champion!



The School for Champions helps you become the type of person who can be called a Champion.