First term ,a=4 , common difference =4-7=-3, n =50
sum of first 50terms= (50/2)[2×4+(50-1)(-3)]
=25×[8+49]×-3
=25×57×-3
=25× -171
= -42925
derivation of the formula for the sum of n terms
Progression, S
S=a1+a2+a3+a4+...+an
S=a1+(a1+d)+(a1+2d)+(a1+3d)+...+[a1+(n−1)d] → Equation (1)
S=an+an−1+an−2+an−3+...+a1
S=an+(an−d)+(an−2d)+(an−3d)+...+[an−(n−1)d] → Equation (2)
Add Equations (1) and (2)
2S=(a1+an)+(a1+an)+(a1+an)+(a1+an)+...+(a1+an)
2S=n(a1+an)
S=n/2(a1+an)
Substitute an = a1 + (n - 1)d to the above equation, we have
S=n/2{a1+[a1+(n−1)d]}
S=n/2[2a1+(n−1)d]
When it says to estimate, I always think of doing it by hand to show work. So set it up like this:
96
<u>x 34</u>
So follow it out multiplying across 4*6 and 4*9 carrying over as needed to get it to look like this:
96
<u>x 34</u>
384
Do the same for the 3 to get this:
96
<u>x 34</u>
384
2880
Add 384+2880=3264
Your final answer is 3,264
94.985 using 3.14 or 95.033 using pie directly
Step-by-step explanation:
This is the answer if the radius is 5.5, half of 11. square it multiply by pie
The answer is 76 divided by 9 equals 8.44
Inc on (-inf,0)
Dec on (0,inf)
