Weekly Math Problem #72

Limits. I found this week's problem in my personal archives. 😁 I'm inspired by students I'll be working with that are learning limits. I can recall learning the concept of what a limit is and how to evaluate the limit of various types of functions. Honestly, I learned limits more after my Calculus 1 course as tutor than when I was enrolled in the course. Repetition really is the key 🗝 for me. Seriously, if I don't use it, I can definitely lose it. **Whispering** "This is why I started my blog." 😊

To solve this week's problem in completion, you need to recall the following math skills:

        ✔️     Substitution        
        ✔️     Simplifying rational expressions
        ✔️     Web Resource: Limits (Evaluating)

             

WMP! #72 want us to...

Happy solving!

Check back on Saturday, February 5th for the solution, which will be posted below ⬇️.

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Buy Me a ☕️ Coffee: TheYoungeLady ( I'm gonna need it this year. 😆 )

✏️📓 Solution Time! 📓✏️

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To begin the process of finding the limit, we'll use the substitution method. 

Unfortunately, the substitution method yields an indeterminate form expression. What does that mean? 🤷🏿‍♀️ This means that the method used doesn't tell us whether or not the limit exists. Another method for evaluating the limit needs to be used to determine whether or not the limit exists.

The numerator of the expression is a cubic polynomial that can be factored. The form is a difference of cubes. When the cubic expression is factored, you will see that one of the factors matches the expression in the denominator. **Yes!** So, we'll simplify the expression. This time, the substitution method will work.

Nice. The limit does exist, and it's equal to 3. 

Another method that can be used to evaluate a limit that yields and indeterminate form is L'Hôpital's Rule. It involves using derivatives and yields the same results. Take a look...

I didn't do it here, but you can graph the original expression and the simplified expression to see what their graphs look like. Then verify that as x approaches 1 from the left and right, the output value is 3.

▪️ Were you able to find the limit?
▪️ Did you do something else to find the limit? If so, please share. (No judgment.)

▪️ Let me know what you thought about this week's problem in the comments section. 

Thank you for solving with me this week. 😊
Up next...WMP! #73. 

Cheers!

The Younge Lady

Weekly Math Problem! #41

Arc Length. Nothing strange going on here this week. I'm just getting back to a calculus problem I wanted to do last week, this week. A little application situation in the form of finding the arc length. 👀 There are times when it is needed to find the length of a curve and there aren't any regular geometric techniques that'll help with that, so calculus steps in to save the day. 😁

To solve this week's problem in completion, you need to recall the following math skills:

        ✔️     How to find the first derivative
        ✔️     How to work with hyperbolic functions
        ✔️     How to do integration

WMP! #41 says to:

Happy solving!

Check back on Friday, March 12th for the solution, which will be posted below ⬇️.

Shameless 🔌 Plug: Follow me on Instagram @TheYoungeLady
Buy Me a ☕️ Coffee: TheYoungeLady ( I'm gonna need it this year. 😆 )

✏️📓 Solution Time! 📓✏️

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And we're back to get this problem done. So, let's see... The problem is asking us to find the arc length of a function on a closed interval. There is a formula for such a situation.

In regards, to our problem, we need to identify the function, take its first derivative, and use the interval. Starting with the function, we're dealing with hyperbolic cosine who has a first derivative that is hyperbolic sine.

Now that we have the first derivative of the function and the interval, we can plug the information in the formula and perform the integration. Remember, we will come out with a numerical answer that represents the length of the function (a curve) for the specified endpoints; it makes that we are working on a definite integral.

As you can see, the arc length of f(x) = cosh(x) on [0, ln 2] is 3/4 units. Let me point out that a scientific or graphing calculator can easily evaluate hyperbolic functions for you. However, I still evaluated it by hand so you can see exactly where the final answer comes from. To assist in evaluating by hand, the exponential representation of hyperbolic cosine is used.

Here is an image of the given function and the part of the function for which we found the arc length.

 

**This plot was created using Geogebra's Graphing Calculator. Click image to enlarge.

 

▪️ We're you able to find the arc length?

▪️ Leave your response down below and let me know what you thought about this week's problem.

Thanks for solving with me this week!

Moving right along to WMP! #42. 👩🏿‍🏫

Cheers!

The Younge Lady

Weekly Math Problem! #30

De Moivre's Theorem. Sometimes, when I'm thinking about what problem to post for the week, topics just come to mind. Somehow, DeMoivre and his theorem was this week's winner. 🎉 The last time I really encountered this topic was well over five years ago...way back when I took a precalculus course. Now that I think about it, 🤔 I don't recall going over this topic in any tutoring sessions over the years. But then again, I've been tutoring for a long time and may not really remember if I actually did or not. 🤷🏿

I would also like to say the following: When I learned this topic, I was enrolled in a summer school course--about four weeks long. I learned the topic quickly without knowing what the practical applications of the theorem is. It felt like the topic was being learned for the sake of learning it, without any real-world connections being made. Even though I didn't ask the question then, I can ask it now and find an answer somewhere on this internet. Okay, I am done with that small rant. 

To solve this week's problem in completion, you need to recall the following math skills:

        ✔️     How to convert complex numbers to polar form
        ✔️     How to apply DeMoivre's Theorem to find powers of complex numbers
        ✔️     How to evaluate trigonometric functions

WMP! #30 wants us to...

Happy solving!

Check back on Friday, December 4th for the solution, which will be posted below ⬇️.

Shameless 🔌 Plug: Follow me on Instagram @TheYoungeLady
Buy Me a ☕️ Coffee: TheYoungeLady

✏️📓 Solution Time! 📓✏️

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Lowkey, I was a little annoyed by the question, after I began solving it. 😒 I didn't realize the numbers were gonna be this crazy. 😅  As soon as I saw 520 ...👀...smh...no words. I realized it was too late to turn back now, so I pushed forward to finish. I will say this, I was getting nervous about whether or not I was correct and needed to verify my numbers. Oh the anxiety I was having. 

Before applying De Moivre's Theorem, some preliminary calculations need to be performed.

Notice, I rounded the angle, 𝛳, in degrees to the nearest thousandth. I didn't want use radians because I am more comfortable with degrees. Next up, the application of De Moivre's Theorem.

Do you see what I mean about the numbers being crazy? 🤪 ...in the trillions! I am aware that answer above is not as accurate as it should be, due to my rounding of 𝛳 to the nearest thousandth. So, I have prepared a more accurate calculation below. 

My final thought: I didn't find the problem difficult to execute. Anxiety was triggered in me when I saw the first large number in my calculation. The anxiety lead me to begin doubting my mathematical abilities. Even though I am good at math, I still very much understand, what it feels like to be fearful when doing it.

▪️ What kind of emotions do you feel when doing math??

▪️ Comment below with your responses and let me know what you thought about this week's problem.

Thanks for solving with me this week!

Up next...WMP! #31

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Cheers!

The Younge Lady