Question

what is the summation notation for the series? 200+175+150+125+___+(-300)

Answer 1

  21
  E    (225-25n)
n=1
So its D.

Answer 2

Answer:

Sum notation will be $\sum_{n=1}^{21}(225-25n)$

Step-by-step explanation:

The given series is 200 + 175 + 150 + 125........+(-300)

Here $T_{n}=a+(n-1)d$

a = 200

d = -25

T(n) = -300

Therefore from the equation

-300 = 200 + (n-1)(-25)

200 -25n + 25 = -300

225 - 25n = -300

-25n = -300 - 225 = -525

n = (-525)/(-25) = 21

Now $T_{n}=200+(n-1)(-25)$

$T_{n}= 200+25-25n = (225-25n)$

Now the notation will be

$\sum_{n=1}^{21}(225-25n)$