An hourglass is turned over with the top part filled with
sand. after 3 minutes, there are 855 ml of sand in the top half. after 10
minutes, there are 750 ml of sand in the top half. This can be represents a two
points ( 3, 855) and (10, 750) . using this to solve the slope m =
(750-855)/(10-3) = -15. And using one point the equation is y = -15x + 900.
area of playground= 9×15= 135m^2
area of lawn= 3×4=12m^2
total flooring area= 135-12= 123m^2
cost=36×123=$4428
AnswerMove
150
150
to the left of
a
a
.
150
a
,
2
h
o
u
r
s
Step-by-step explanation:
I'm only going to alter the left hand side. The right side will stay the same the entire time
I'll use the identity tan(x) = sin(x)/cos(x) and cot(x) = cos(x)/sin(x)
I'll also use sin(x+y) = sin(x)cos(y)+cos(x)sin(y) and cos(x+y) = cos(x)cos(y)-sin(x)sin(y)
So with that in mind, this is how the steps would look:
tan(x+pi/2) = -cot x
sin(x+pi/2)/cos(x+pi/2) = -cot x
(sin(x)cos(pi/2)+cos(x)sin(pi/2))/(cos(x)cos(pi/2)-sin(x)sin(pi/2)) = -cot x
(sin(x)*0+cos(x)*1)/(cos(x)*0-sin(x)*1) = -cot x
(0+cos(x))/(-sin(x)-0) = -cot x
(cos(x))/(-sin(x)) = -cot x
-cot x = -cot x
Identity is confirmed
