-103
Step-by-step explanation:
a(1) = 12
a(n) = a(n-1) - 23
a(2) = a(1) - 23
= 12 - 23
= -11
Common difference (d) = a(2) -a(1) = -11 - 12 = -23
a(n) = a1 + (n-1)d
a(6) = 12 + 5 * (-23)
= 12 - 115
= -103
56
The n th term of an AP is
= a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Given a₆ = 17 and a₁₃ = 38, then
a₁ + 5d = 17 → (1)
a₁ + 12d = 38 → (2)
Subtract (1) from (2) term by term to eliminate a₁
7d = 21 ( divide both sides by 7 )
d = 3
Substitute d = 3 into (1) and evaluate for a₁
a₁ + 5(3) = 17
a₁ + 15 = 17 ( subtract 15 from both sides )
a₁ = 2
Thus
= 2 + (18 × 3) = 2 + 54 = 56
20th term= 119
Let the first term of AP be a
and common difference be d
nth term is given by,
= a+(n-1)d
6th term = 35
a+(6-1)d= 35
a+5d=35 (i)
13th term = 77
a+12d= 77(ii)
Now, equation (ii) - (i)
a+12d-(a+5d)= 77-35
a+12d-a-5d= 42
7d=42
d=6
Now, from equation (i)
a= 35-5d= 35-5(6)= 35-30 = 5
20th term= a+19d= 5+19(6)= 119
5
The 6th term of an arithmetic progression is 35 and the 13th term is 77. find the 1st term
We know we have an arithmetic sequence.
a_n = (n - 1)*d + a_1
given:
a_6 = 35 = (6-1)*d + a_1
a_13 = (13 -1)*d + a_1 = 77
find a_1
we have 35 = 5d + a_1
and 77 = 12d + a_1
2 equations in 2 unknowns.
We can solve this.
77 = 12d + a_1
35 = 5d + a_1
minus the 2 equations from each other.
77 - 35 = 12d - 5d + a_1 - a_1
42 = 7d
d = 6
Find a_1
35 = 5*6 + a_1
35 = 30 + a_1
a_1 = 35 -30 = 5
a_1 = 5
16
Let's set the arithmetic : -4,0,4,8,x,y,...
The number we need to find is y
We have:
-4 + 4 = 0
0 + 4 = 4
4 + 4 = 8
So:
x = 8 + 4 = 12
y = x + 4 = 12 + 4 = 16
Then the 6th term of the arithmetic is 16 !
Brainliest, please?
a(first term)=4
d(common difference)=6
sum of first 6 terms=114
It will provide an instant answer!