Answer:
2hrs 40 minutes
Step-by-step explanation:
The formula for distance is expressed as:
#The time taken to run:
#The time taken to walk:
#Since the distances are the same:
Hence, Dana spends 2hrs 40 minutes walking back
follows from the fact that the cosine function is
-periodic, which means
. Roughly speaking, this is the same as saying that a point on a circle is the same as the point you get by completing a full revolution around the circle (i.e. add
to the original point's angle with respect to the horizontal axis).
If you make another complete revolution (so we're effectively adding
) we get the same result:
. This is true for any number of complete revolutions, so that this pattern holds for any even multiple of
added to the argument. Therefore
for any integer
.
Next, because
, it follows that
is also true for any integer
. So we have
The rest follows from considering either case and solving for
.
Answer:
There are only 1
Pairs of integers satisfying a÷b = -2
Step-by-step explanation:
The inequality is still true! If you add a number, say 5 to both sides of the following inequality, does anything change?
3 < 6
3 + 5 < 6 + 5
8 < 11
The inequality is still true. We know the statement holds for subtracting the same number because, in a way, addition and subtraction are pretty much the same operation. If I subtract 5 from both sides, I can think of it like "I add negative 5 to both sides" or something along those lines. It's kind of backwards thinking.
