Answer:
3/5
Step-by-step explanation:
We need to use the trig identity that cos(2A) = cos²A - sin²A, where A is an angle. In this case, A is ∠ABC. Essentially, we want to find cos∠ABC and sin∠ABC to solve this problem.
Cosine is adjacent ÷ hypotenuse. Here, the adjacent side of ∠ABC is side BC, which is 4 units. The hypotenuse is 2√5. So, cos∠ABC = 4/2√5 = 2/√5.
Sine is opposite ÷ hypotenuse. Here, the opposite side of ∠ABC is side AC, which is 2 units. The hypotenuse is still 2√5. So sin∠ABC = 2/2√5 = 1/√5.
Now, cos²∠ABC = (cos∠ABC)² = (2/√5)² = 4/5.
sin²∠ABC = (sin∠ABC)² = (1/√5)² = 1/5
Then cos(2∠ABC) = 4/5 - 1/5 = 3/5.
(B) a earth worm i think!I hope this helps:)
16-20 are correct. <em>Remember to mark the first #20 as A</em>
The last #20 is wrong. The answer is B. 95 minutes.
10:55 - 11:00 = 5 minutes
11:00 - 12:00 = 60 minutes
<u>12:00 - 12:30</u> = <u>30 minutes</u>
Total = 95 minutes
Answer:
35• 43 m square is correct answer
8sin(x)cos(y) = 6
Take derivative with respect to x. Since y is a function of x, take the derivative for y as well but it is multiplied by dy/dx
chain rule
8cos(x)cos(y) - 8sin(x)sin(y)(dy/dx) = 0
solve for dy/dx
8cos(x)cos(y) = 8sin(x)sin(y)(dy/dx)
[8cos(x)cos(y)]/[8sin(x)sin(y)] = dy/dx
simplify
cot(x)cot(y) = dy/dx
