Wednesday, May 15, 2019

Notes for Homework #13


Notes on parametric equations

Usually, we have a function with two variables, the dependent variable if either y or f(x) and the independent variable is x. In this case, we will instead have an independent variable t and two equations that are dependent on t, which in this case can be thought of as time measured in seconds. 

We will consider the path of a projectile being acted upon by gravity, where H(t) is the height and D(t) is the distance. We need two numbers to define our functions, v0 is the initial velocity - known as muzzle speed - and the angle at which the project is launched, which we will call theta. The two formulas are as follows, measuring time in seconds and height in feet

H(t) = t(sin(theta)v0 - 16t)
D(t) = t(cos(theta)v0)

Height will be 0 at t = 0 and when sin(theta)v0 - 16t = 0, which can be thought of as the launch and the landing, respectively.
When you solve the landing time, plug in that t into D(t) to get how far the projectile will travel before it hits the ground.


Notes on the angle between two vectors

Friday, April 26, 2019

Notes for Homework #12, due Tues. Apr. 30 NOT ACCEPTED LATE

Notes for converting polar to Cartesian and vice versa

Note for plotting polar coordinate functions

The website Wolfram Alpha is a good resource for plotting. For example, use the instruction

plot r = cos(theta)

To see an accurate picture of a circle with its center at (= ½, 0) and radius = ½, passing through both (0, 0) and (1, 0)

Note: The x-axis is all points of the form (x, 0) in Cartesian coordinates. The form looks exactly the same in Polar coordinates, since the angle 0 is the x-axis.

Wednesday, January 23, 2019

Notes for homework #1, due Jan. 29

Notes on the triangle inequality

Classifying triangles defined by side lengths
Let the three sides be called a, b and c, where c is the longest side.

There are three possible relationships between the sum of the squares of a and b and the value c². 

a² + b² > c²   This means the triangle is acute.
a² + b² = c²   This means the triangle is right. This is the Pythagorean Theorem,
a² + b² < c²   This means the triangle is obtuse

Here are some practice problems
     

Given one angle measurement, create an isosceles triangle. If the angle is acute, there are two possible isosceles triangle.

Notes on Heron's Formula and practice problems