Further Trigonometry - Chapter 6

Hello future Mathematicians! 

Let's take a journey to explore triangles and their angles. 

 

Image result for right angled triangle hypotenuse

Task 1: Recap on acute angles

Step 1:

Watch the following youtube video.

 

Task 2: Obtuse Angles

Image result for acute obtuse and right angles

Step 1: Extend the definition of trigonometric ratios.

Question 1: 

What will cosine theta and sine theta be if the circle is of radius r instead?

 

Step 2:

Do the Investigation on page 175 in your textbook. 

Question 2:

What can you conclude from the Investigation?

 

Step 3:

Look at the Conclusion tab for the answers of Question 1 and 2. Do Practise Now 1 and 2 in your notebook. 

 

Step 4:

Give yourself a pat on the back. You have completed your elearning! :D

 

Question 1

Answer: cosine theta = x/r  and  sine theta = y/r

 

Question 2

Answer: sin A = sin (180-A)  and  cos A = -cos (180-A)