Help! Give me the answer. I'll give the BRAINLIEST
1 answer:
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Answer:
8 seconds.
Step-by-step explanation:
To solve this question, we need to find the time, , when
, that is, when the height of the object above the ground is 0 feet.
Substituting feet per second and
gives the quadratic:
Since 128 is divisible by 16, it can be reduced to .
We must now solve for .
We can easily see that one answer to the equation is 0,
(we need not concern ourselves with the 16 outside of the parenthesis as in the equation above, since 16 multiplied by 0 is 0). However this is the time the object is released into the air.
The second answer, is also easy to see by inspection:
.
Therefore the object lands 8 seconds after it is thrown.
Answer:
A. -2sin(x)sin(0.4x)
Step-by-step explanation:
At x=0, the given expression evaluates to zero.
For x near zero, the given expression is slightly negative. You know this because cos(1.4x) decreases faster than cos(0.6x), so their difference will be negative.
Of the answer choices, you can eliminate C and D because they are not zero at x=0. You can eliminate choice B, because it is positive for values of x near zero. The only viable choice is A:
-2sin(x)sin(0.4x)
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Of course, a graphing calculator can help you figure this out. See the attachment. The given expression is plotted using a solid red line; the answer choice A is plotted using blue dots.
