Write the first five terms of the sequence whose nth terms are: An = 2n- . 3n
Answers
Answer:
next term = 5
Step-by-step explanation:
5,10,15,20...
Given:
- An Arithmetic Progression[AP] whose nth term is given by 2n - 3n.
Find:
- First 5 Terms of the AP.
Solution:
Let us first find the first 2 terms of the AP whose terms are given by the formula: 2n - 3n.
For n = 1:
a₁ = 2(1) - 3(1).
a₁ = 2 - 3.
a = a₁ = -1.
For n = 2:
a₂ = 2(2) - 3(2).
a₂ = 4 - 6.
a₂ = -2.
Now, common difference d is given by the formula:
So, the common difference in this case is:
d = a₂ - a₁.
d = -2 - (-1).
d = -2 + 1.
d = -1.
Now, let us check that -1 is the common difference.
We can do so by checking the difference of any 2 terms.[Other than the ones we have used already]
Finding the third term:
a₃ = 2(3) - 3(3).
a₃ = 6 - 9.
a₃ = -3.
Checking if our common difference is right:
d = a₂ - a₁ = a₃ - a₂.
a₂ - a₁ = -1.
a₃ - a₂ = -3 - (-2) = -3 + 2 = -1.
∴ a₂ - a₁ = a₃ - a₂.
∴ d = -1.
We know that the General Form of an AP is:
a, a+d, a+2d, a+3d, ...., a+(n-1)d.
Therefore, the first 5 terms of the AP are:
-1, -2, -3, -4, -5.