BQ#4 Unit T Concepts 1-3 Tangent & Cotangent graphs

Why is a “normal tangent graph uphill but a “normal” cotangent graph downhill?

The graphs for tangent and cotangent are in every single way bit for some reason they end up looking weird at the end. This is because of the way their asymptotes are formed. We know that tangent and cotangent are (+) in quadrants 1 & 3, and (-) 2 & 4. To understand this more, remember that to get an asymptote the trig ration must be undefined to have an undefined ratio you need to divide by zero.

For tangent, we know the ratio is Y/X so... to get an asymptote X must equal to zero. This means to will have asymptotes at pi/2 & 3pi/2. So the graph of tangent cannot touch these lines, but somehow it must be are in quadrants 1 & 3, and (-) 2 & 4. The only way to draw this is making it look like it is going “uphill”

Cotangent, we know the ratio is X/Y so… it will have asymptotes wherever cos=0 or y=0. This means the graph will have asymptotes at 0, pi, 2pi. The only way to graph this is how we did it above, giving it a “downhill” looking graph.

BQ #3: Unit T Concept 1-3

How Do The Graphs of Sine and Cosine Relate To Each of The Others?

2nd quadrant

1st caption

The graphs of sine and cosine relate to the others through their asymptotes. If you remember, we can think of a graph as an unraveled unit circle. If we think of it like this than sine and cosine can relate to the other functions through the quadrants. Another thing that will help us bring everything full circle are the trig identities. If you need reference to the graph on desmos you can click here courtesy of Mrs. Kirch

Tangent?

One thing that will aid the explanation of this is are the trig identities. Recall that tan= sin/cos if you take a look at the graph the green (sin) and red (cos) lines are positive because they are above the x axis. If we use this in the identity it means that is sin and cos are positive than tangent will be positive, as you can see this is true because the tangent graph is above the x axis. In the second picture, one of the graphs is positive one is negative giving it an overall negative, this is the reason why the tangent graph is below the x axis. These are some of the ways that the graphs relate.

Cotangent?

The explanation for  cotangent will be much more concise because it is based on the rules as tangent. For the exceptions that the identity is cos/sin and the asymptotes are shifted over. The asymptote will be at 0,pi, and 2pi. Also,  The graph of cotangent has its asymptotes based on sine.

Secant?

Secant relates to cosine because it has asymptotes based on cosine its asymptotes are where cos is equal to zero. This is because an asymptote is formed when secant is undefined, and the ratio for secant is R/X to get this to be undefined X=0.

Cosecant?

The asymptotes of cosecant are based on sine. It has asymptotes where sine equals zero because the ratio must be undefined. The ration so cosecant is R/Y to get an asymptote Y=0

BQ#5 - Concepts 1-3

Why do sine and cosine NOT have asymptotes, but the other four trig graphs do?

From the picture above we see that sine and cosine are always divided by R wich means they will be divided by 1. This means that they cannot be undefined. Of your ratio isnt undefined then you wont have an asymptote. Other trig functions it is possible to have asymptotes because you can divide by 0. And, as we know dividing by zero equals undefined wich cause asymptotes in graphs.

BQ#2 - Unit T Concept 2

How do trig graphs relate to the Unit Circle?

a. The period for sine and cosine is 2pi because thats is howl long it takes for the    pattern to repeat. By pattern I mean for the positive and negative quadrant patterns. We know that a trig graph of sine is ++-- this means that the first to quadrants of the graph will be above the X axis and the othe will be under. Tangent /Cotangent however, will be pi because you only need one section for the pattern to repeat. The pattern for tangent/cotangent is +-+- however you only need +- because the pattern repeats  already.

b. Sine and cosine have restrictions because the unit curcle is only goes up to. 1, -1, 0. For the same reason sine and cosine can only equal >-1 & <1. To quote  Mrs. Kirch, " Sine and Cosine cannot bust through the restrictions."

Reflection# 1: Deriving trig identities

Reflection

1.What does it actually mean to verify a trig identity?

-to verfify and identity you should get both sides equal to the same trig function. You simplify the messy side and then when yiu get the same trig on that side it is verified

2.What tips and tricks have you found helpful?

- One tip that i found helpful is converting the trigs to sin / cosine. If you have tan and cot you can switch those to sin and cos. this really helped me because it gives me something to do and gets my brain working. This is much better then just starring at a problem for 10 minutes. Another truck that i use when I am stuck is to split fractions. Split fractions is easier for me to work with then a big fraction.

3.Explain your thought process and steps you take in verifying a trig identity.  Do not use a specific example, but speak in general terms of what you would do no matter what they give you.

- when ever i am having trouble the first thing i look for is sibstituting an identity. If you cant plug this in then converting to sin/cos helps. Other than this you might be able to find a GCF in the equation. As a last resort square both sides and the. Find extrannneous solutions.

SP#7: Unit Q Concept 2

This SP7 was made in collaboration with Sarah Ngo.  Please visit the other awesome posts on their blog by going here. www.sarahnperiod1.blogspot.com