In this week, I learned about the sine law and the cosine law.
I chose these topics because I never learn about these law in my life. Also, I thought these laws are really useful.
The sine law: In every triangle ABC,
I tried to solve practice paper number 8.
At first, check the information which I got.
I could see two angles and 1 line value.
So, I should use the sine law in this time.
sin15° divide 10 = sin25° divide X.
I changed this equation like this,
x = 10 sin25° divide sin15°
After this calculate, I could get x = 16.
Answer is 16m.
Next, I talk about the cosine law.
The cosine law: In every triangle ABC,
I tried to solve practice paper number 1.
At first,check the information which I got.
I got 1 angle and 2 lines value.
So, I should use the cosine law in this time.
I could write equation like this,
z square = 20 square + 10 square – 2(10)(20)cos 40°
After calculate, I got z=13.9
This is answer.
Overall, the most important thing is check the information and figure out which method to use.