Since

, and you have a corresponding term in the given Riemann sum of

, you know the integral is being taken over an interval of length 5, so you can omit the second choice.
Next,

corresponds to

with

. The fact that

alone tells you that the interval of integration starts at 3, and since we know the interval has length 5, that leaves the first choice as the correct answer.
Answer:
7.5 seconds
Step-by-step explanation:

Thus, the time required for the object to return to its point of departure is 7.5 seconds.
Answer:

Step-by-step explanation:
see the attached figure to better understand the problem
we know that
The area of triangle ABC applying the law of sines is equal to

substitute the given values


Answer: 12<5x+4
Step-by-step explanation: