Answer:
1/3
Step-by-step explanation:
In statistics, the probability of both an event A and an event B happening is equal to the probability of A happening multiplied by the probability of event B happening.
Let's say spinning a prime number is event A and rolling a number ≤ 4 is event B.
There are 8 possibilities on an eight equal segment spinner, and there are 4 prime numbers between 1 and 8 (including 8), which are 2, 3, 5, and 7. This means that the probability of spinning a prime number is 4/8, or 1/2
There are 6 possibilities on a die, and there are 4 possibilities of rolling a 4 or less (1, 2, 3, 4). Therefore, the probability of rolling 4 or less on a die is 4/6, or 2/3
The probability of both of these happening can be calculated by multiplying these together, so 1/2 * 2/3 = 2/6 = 1/3
Answer:
√2(√3 - 1)/4
Step-by-step explanation:
To find an exact value for Cos75°, we use the compound angle formula. Since 75° = 45° + 30°, Cos75° = Cos(45° + 30°).
Using Cos(A + B) = CosACosB - SinASinB where A = 45° and B = 30°,
Cos75° = Cos(45° + 30°) = Cos45°Cos30° - Sin45°Sin30°
Now Cos45° = Sin45° = 1/√2 = √2/2, Cos30° = √3/2 and Sin30° = 1/2.
Substituting these values into the above equation, we have
Cos75° = Cos(45° + 30°)
= Cos45°Cos30° - Sin45°Sin30°
= √2/2 × √3/2 - √2/2 × 1/2
= √6/4 -√2/4
= √2(√3 - 1)/4
1 negative startroot 2 end root 1 start root 2 end root
