9514 1404 393
Answer:
-2cos²(x) +3cos(x) -1
Step-by-step explanation:
Use the "Pythagorean identity" to replace sin²(x).
sin²(x) +cos²(x) = 1
Then ...
2sin²(x) +3cos(x) -3 = 2(1 -cos²(x)) +3cos(x) -3
= -2cos²(x) +3cos(x) -1
Answer:
2/3
Step-by-step explanation:
If you divided 2 by 3, you will get 0.6 repeating.
Consider this option:
1. if to re-write the condition, it is given: total time t=8 hours; upstream=downstream=6 miles; V_boat=4 m/h., V_current=V=?
2. note, that total time=time_upstream+time_downstream, where time_upstream=6miles/(V_boat-V) and time_downstream=6miles/(V_boat+V). Using this it is possible to make up and solve the following equation:

answer: √10
P.S. the roots of the equation are √10 and (-√10), only positive values is needed for V.
1/3 of 5/8...." of " means multiply
1/3 * 5/8 = 5/24 lbs