Sum of an infinite geometric sequence with the common ratio r, and the first term a1 is
we notice
-2 times -1/4=1/2,
1/2 times -1/4=-1/8
so a1=-2
r=-1/4 or -0.25
so the sum is
=
=
=
=
the sum is -8/5 or -1.6
what is the best and easiest method to use to find sides A and B?
B
The line passes through two points that have the same x-coordinate.
It is a vertical line. To find the slope of a line, use any two points. Subtract the y-coordinates. Subtract the x-coordinates in the same order. Then divide the difference of the y-coordinates by the difference of the x-coordinates. Since in this case, the x-coordinates are both -6, the difference between the x-coordinates is zero. Division by zero is not defined, so the slope of this line is undefined. You can't write its equation in point-slope form, because there is no slope for this line.
Length of train : 100
length of bridge : 400
distance covered by the train to cross the bridge : (100 + 400) = 500
time taken by the train to cross : 30
speed = distance / time
speed = 500/30
speed = 16.67 meters per second <===
