The period of y = 4 cos(8πx) is 2π/(8π) = 1/4, since
cos(x - 2π) = cos(x)
and if we replace x with 8πx, we get
cos(8πx - 2π) = cos(8πx)
and
8πx - 2π = 8π (x - 1/4)
Yes this equation is an identity.
This is how I would do it;
Convert to minutes 3/5 *60 = 36
Convert this to decimal 2/5 = 0.4
Then;
if it takes 36 mnts to paint 0.4yd^
in 60 mnts x yd^
___________________
60 x 0.4 / 36 = 0.66666667
convert back to fraction = 2/3 yd^ in 1hr
Answer:
i think 10mph
Step-by-step explanation:
if she ran 100% faster that means she ran double or 200% of the initial speed
Let's say that number is hmmm "a"
now.. twice "a" is 2*a or 2a
4 less than that is " 2a - 4"
now, the product of those two fellows is 286, well ok
a( 2a - 4) = 286
thus