How many complete rotations does the minute hand of a clock make as it moves from 12:00 noon to 4:00 p.m.?
2 answers:
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Answer:
The value of cos Ф is ±
Step-by-step explanation:
There are important rules for sin Ф and cos Ф
- sin²Ф + cos²Ф = 1
- sin²Ф = 1 - cos²Ф
- cos²Ф = 1 - sin²Ф
∵ sin Ф =
∴ sin²Ф =
∴ sin²Ф =
→ By using the third rule above
∵ cos²Ф = 1 - sin²Ф
∴ cos²Ф = 1 -
∴ cos²Ф =
→ Take square root for both sides
∴ cos Ф = ±
∴ The value of cos Ф is ±
Answer:
and
Step-by-step explanation:
Think about it.
What two numbers multiply to -15 and add up to 2?
The answers are 5 and -3.
So plug that into the factored form of a parabola.
To find the x-intercepts, plug in 0 for .
Since we are multiplying, at least one of the terms has to equal 0.
So the x-intercepts are and
.