# TI-89 Calculator and Batteries Cozy

Well, since I was making storage pocket things, I decided to make a calculator cozy for my TI-89. I also needed a place to hold extra batteries, because I’d rather not be in the middle of a test and have my calculator die with no back up batteries available. Yes! This does happen! I’m still debating about adding the extra ribbons on top to secure the calculator, but I don’t know if it really needs it, because it fits pretty snug. I made this out of the Mars Martian fabric that I created. :) UPDATE: I decided to add the bows for closure. :)

# Cats with Parachutes in Math Books!

I just posted this on my FB page, but I had to post here. I think this is so funny. This pic comes from my Differential Equations textbook. They were talking about modeling using differential equations, and in the process talked about cats falling from high rises, so they included this pic of a cat with a parachute! Math nerds rock! :) lol

# Having Fun with Ellipsoids!

We are currently working on understanding strange things like ellipsoids and hyperbolic paraboloids and all sorts of strange things like that in my Calc 3 class. It seems like it wouldn’t be that hard, but it is pretty hard to draw these things correctly! This week we got a take home quiz! Thank goodness! I’m posting one example where we are supposed to name the shape and then draw it and talk about the plane sections that intersect it. I don’t know if I’m doing it correctly or not. Guess I will find out!

Basically, how you know it is an equation for an ellipsoid is that an ellipsoid has a standard form for the equation which is basically (x/a)^2 + (y/b)^2 + (z/c)^2 = 1. Now there are many variations on that, so that it might look a bit different, but if it is too different it will be a different shape, like a hyperboloid of one sheet or something else like that. The a’s give you the ellipse size along the x-axis, the b’s give you the ellipse parts for the y-axis and the c’s give you the ellipse information for the z-axis. It is kind of hard to explain in words! lol I guess what you first need to know is that a regular old ellipse is drawn on the x and y axis where the a number gives you information on the number of steps away from the origin along the x-axis and the b number gives  you the number of steps away from the origin along the y-axis. I guess I better post an example.

In the example below #1b, you look at the bottom numbers to give you the size of the ellipse. The x-axis number is 5, so it is five units wide on each side. The y-axis number is 10, so it is 10 units wide on each side of the origin. The x-3 and y-3 has to do with shifting the graph away from the origin up and over 3 units each.

Anyway, from what I can gather, to draw the ellipsoid (not ellipse) like in example 2a, you need to draw the various ellipses that make up the ellipsoid in order to get the final shape, so you set x, y and z equal to zero for three different cases to get your ellipse equations. Blah blah blah. This probably makes no sense to anyone, but I thought I’d share! lol

Hyperbola (top) and Ellipse (bottom)

Ellipsoid Example

# New Calculus Fabric Arrived Today!

More Calc2 Fabric

Orange Chevrons with Balloons

I made another Calculus fabric through spoonflower (http://www.spoonflower.com/fabric/1187406), because I was so excited about my first Calculus fabric. Well, the material arrived in the mail today! How exciting!!! I also got my design of balloons on orange chevrons, but I have to work on perfecting the chevrons and getting it how I like it. So fun to get fabric in the mail! :) Click the photos for a larger view. :)

# Yellow-Backed Calculus Pillow

Calculus Pillow

I just finished making my yellow-backed Calculus pillow. It has soft fleece on the back and my Calculus fabric that I made on the front. Here is the link for the Calc Fabric: http://www.spoonflower.com/fabric/1147427. It took a lot of stuffing to fill it, and I probably should have made it with an insert instead of filling, but meh! I love it anyway! Should help me get comfy when I need to do my Calc homework! haha. And yes, it is made from actual Calculus homework! :) Yay!!!

# It Is About Math and Cats People! LOL

Yes, my life is all about math and cats. Here is another cat I’ve finished making. This one is for a friend of mine who likes green. :)

I have one cat for sale in my Etsy shop here: http://www.etsy.com/shop/ArtByKristinBell.

And I’ve made a new Calculus fabric out of my math homework and uploaded it to spoonflower.

Here’s my shop on spoonflower: http://www.spoonflower.com/profiles/kristinbell

OMG I was so excited when someone bought one of my fabrics! You have no idea how thrilling it is!!!

I’m quite a boring person…obsessed with making cats and doing math homework! hehe. Thank god the anxiety has calmed down quite a lot, so I can go about my business and get stuff done!!! What a relief! :) :) :)

# More Fabric From Spoonflower! Yay! Nerd Alert!

Okay, watch out! I’m totally going to nerd out now! I took my calculus homework and created a fabric!!! hahaha Other fabrics include a larger version of the playing kitty, red-white-blue kitty, a neuron, and then I wanted to show you guys what my martiannaut and Judie the Utie look like by the yard! On some I have swatches and fat quarters, because I wanted to see what the repeating pattern was going to look like. The math one is a fat quarter and just a close up of a section of the fabric. It is all so exciting!!! I LOVE FABRIC! If only it were free!!! One of my favorites really is the math one I have to admit! lol Here’s my spoonflower shop address should you feel motivated to get any of my fabrics or if you want to make your own: http://www.spoonflower.com/profiles/kristinbell JUST BEWARE THE ADDICTION!!!! LOL

The Calc2 Fat Quarter with REAL Calc2 Homework!!! hahaha

Calc2 section

Neuron Swatch

Neuron Fat Quarter

Playing Kitty Large Swatch

Playing Kitty Large Fat Quarter

Red, White & Blue Kitty Swatch

Red, White & Blue Kitty Fat Quarter

A yard of Martiannaut

A yard of Judie the Utie

# Calc Example: For When You Hit sqrt(2-2cos(t)) And Need To Integrate!

This example almost made my brain explode! I didn’t know about the Weierstrass substitution method (see this link for more info.: http://en.wikipedia.org/wiki/Weierstrass_substitution) when I began this problem…which is what I needed to complete the problem. I’m still unsure if I did it correctly, because we were supposed to find the integral over 0 to 2*pi, but the integration method only works over 0 to pi, so I ended up multiplying the answer by 2 (because 2 times pi is 2*pi) which got me the answer the book was asking for, but it seemed odd to do it that way. The question is number 18, section 13.3 from the Jon Rogawski Calc book in case you are interested. I think it is a pretty great textbook by the way…I mean as far as math textbooks go! We were also supposed to find when the speed was at its max, but I was so tired I just figured it was at pi and gave up! So, here’s the problem!

# Calc 4 Vector Integration Problem

Let me just say: Calc 4 is confusing!!! We are working with vectors and all sorts of weird 3D shapes and it is strange! Here is an example homework problem. I hope I survive Calc 4!!!