Each number in the sum is even, so we can remove a factor of 2.
2 + 4 + 6 + 8 + ... + 78 + 80 = 2 (1 + 2 + 3 + 4 + ... + 39 + 40)
Use whatever technique you used in (a) and (b) to compute the sum
1 + 2 + 3 + 4 + ... + 39 + 40
With Gauss's method, for instance, we have
S = 1 + 2 + 3 + ... + 38 + 39 + 40
S = 40 + 39 + 38 + ... + 3 + 2 + 1
2S = (1 + 40) + (2 + 39) + ... + (39 + 2) + (40 + 1) = 40×41
S = 20×21 = 420
Then the sum you want is 2×420 = 840.
Y = mx + b
m = (y2 - y1)/(x2 - x1)
y = (26,600 - 18100)/(20 - 10)x + b
y = 850x + b
18100 = 850(10) + b
b = 9600
R(x) = 850x + 9600
When n = 1 first term = -6
n = 2 second term = 0
n = 3 third term = 6
n = 4 4th term = 12
so we have an Arithmetic sequence first term = -6 and common difference = 6
Sum 14 terms = (14/2)[2*-6 + (14-1)*6]
= 462 answer
Answer:
Antonia saved $5.39
Step-by-step explanation:
Candle:
$9.59 - $0.50 (coupon) = $9.09
Towel:
$21.43 - $2.75 (coupon) = $18.68
Dishes:
$21.43 x 10% = 2.143
$21.43 - $2.143 = $19.287, rounded to the nearest cent and it’s $19.29.
Calculate the amount of money saved by adding 0.50 + 2.75 + 2.143, which is 5.393. Round to the nearest cent and it will be $5.39.
Answer:
Triangle 2
Step-by-step explanation:
That is Pythagorean Theorem, which is only for right triangles. The second triangle has the little square, so you know it is 90 degrees.
