Prove the identity cos(3x)=cos^3(x)-3sin^2(x)cos(x), step by step.
1 answer:
You might be interested in
Answer:
Okay, here's the method I'm going to use.
If you drive north 6 miles, and then drive east 19 miles, you are technically making a triangle.
19 miles
l_______________
6 milesl
l
You are just missing the last side of the triangle: the straight line stretching from across your starting point to the ending point. You can find this by using the Pythagorean theorem.
a^2 + b^2 = c^2
6^2 + 19^2 = c^2
36 + 361 = c
397 = c
= 19.924859
Rounded to the nearest tenth, your answer is
19.9 miles