Answer:
None of these
Step-by-step explanation:
The two cases are for trigonometry special angles.
The cosine of an angle is given as the adjacent side length divided by the hypotenuse side length
Cos ∅ = A/H
1. The case of 45°,45°,90°
Cos x = 1 /√2
2. The case of 30°, 60° ,90°
Cos x = 1/2 or √3/2
Eight hundred and ninety-six point eight hundred and fifty-four.
Step-by-step explanation:
We can prove the statement is false by proof of contradiction:
We know that cos0° = 1 and cos90° = 0.
Let A = 0° and B = 90°.
Left-Hand Side:
cos(A + B) = cos(0° + 90°) = cos90° = 0.
Right-Hand Side:
cos(A) + cos(B) = cos(0°) + cos(90°)
= 1 + 0 = 1.
Since LHS =/= RHS, by proof of contradiction,
the statement is false.
Answer:
D. 9990 possible combinations
Step-by-step explanation:
The first digit has 10 choices (can be all of them), the second digit also has 10 choices. The third and fourth digits also have 10 choices.
Multiply them together you get 10*10*10*10 = 10000 possible combinations.
But since all 4 characters cannot be the same, we subtract 10 from 10000 (there are 10 combinations which the 4 characters are the same: 1111, 2222, 3333, 4444, 5555, 6666, 7777, 8888, 9999, and 0000) and we get 9990.
