Pages

welcome text

Welcome to Bryan.A's Math Analysis Blog

Anything you need to learn about math analysis

Thursday, March 20, 2014

I/D3: Unit Q - Pythagorean Identities

Inquiry activity Summary
1.      Where does sin^2x+cos^2x=1 come from to begin with?
a.       To explain this we need to think back and remember basic trig functions. We know that sin=y/r and cos=x/r. The unit circle gives us a value for r which is r=1. We also need to recall that the Pythagorean Theorem is a^2+b^2=c^2. Now we have everything we need to prove this. First we choose an ordered pair form the unit circle, like (1/2,3/2). We can now plug this in to (y/r) ^2+(x/r) ^2=1. The equation we should plug into our calculator is to (1/2)^2+ (3/2)^2=1. This shows how we can use the unit circle and the Pythagorean Theorem to get sin^2x+cos^2x=1.
2.      Show and explain how to derive the two remaining Pythagorean Identities from sin^2x+cos^2x=1
a.      Once you read this paragraph you will definatly realize how easy it is to derive the rest of the Pythagorean Identitites. First, you have your original identity: sin^2x+cos^2x=1 you will divide this by cos^2. Once you have done this your new identity will be 1+tan^2x=sec^2x. To get the next identity you dived the original by sin^2, you will get 1+cot^2=csc^2.

Inquiry Activity Reflection

1. The connection that I see between Units N,O, and P are trig functions, trig ratios, and pythagorean theorem.

2. If I had to describe trigonometry in 3 words, they would be challenging, a little frustrating and rewarding. 

No comments:

Post a Comment