The 2nd and 5th term of G.P are 2/3 and 1/2 respectively.what is the 1st term,the 4th term and the 7th term
Help me
Xn = a r^(n-1)
X2 = a r = 2/3
X5 = a r^4 = 1/2
so
X5/X2 = r^4/r = (1/2)/(2/3)
r^3 = 3/4
r= .75^(1/3)
a r = 2/3
a [.75^(1/3)] = 2/3
solve for a which is the first term
ar^3 = a * (2/3) which is term 4
1 WHOLE NUMBER 1 OVER 3
To find the 1st term, 4th term, and 7th term of a geometric progression (G.P), we can use the formula:
๐๐ = ๐โ ร ๐^(๐โ1)
where ๐โ represents the 1st term, ๐ represents the common ratio, and ๐ represents the term number.
Given that the 2nd term of the G.P is 2/3 and the 5th term is 1/2, we can create the following equations:
๐โ = ๐โ ร ๐
๐โ
= ๐โ ร ๐โด
Substituting the given values:
2/3 = ๐โ ร ๐ ---(1)
1/2 = ๐โ ร ๐โด ---(2)
Now, we can solve this system of equations to find ๐โ and ๐.
Step 1: Solve equation (1) for ๐โ in terms of ๐:
From equation (1), ๐โ = (2/3) รท ๐
Step 2: Substitute the value of ๐โ from Step 1 into equation (2):
1/2 = [(2/3) รท ๐] ร ๐โด
Simplifying equation (2):
1/2 = (2/3) ร ๐ยณ ---(3)
Step 3: Solve equation (3) for ๐:
Multiply both sides of equation (3) by 3:
(1/2) ร 3 = 2 ร ๐ยณ
3/2 = 2๐ยณ
Divide both sides by 2:
3/4 = ๐ยณ
Take the cube root of both sides:
โ(3/4) = ๐
Simplify:
๐ = โ3/โ4
Step 4: Now that we know the value of ๐, we can substitute it back into equation (1) to find ๐โ:
From equation (1), 2/3 = ๐โ ร (โ3/โ4)
Multiply both sides by โ4:
(2/3) ร โ4 = ๐โ ร (โ3/โ4) ร โ4
Simplifying:
2โ4/3 = ๐โ ร (โ3)
Divide both sides by โ3:
(2โ4/3) รท (โ3) = ๐โ ร (โ3) รท (โ3)
Simplifying:
2โ4/3โ3 = ๐โ
Step 5: Simplify the value of ๐โ:
Multiplying the radicals:
2โ(4ร3) / 3โ(3ร3) = ๐โ
Simplifying:
2โ12 / 3โ9 = ๐โ
Further simplifying:
2โ(2ร2ร3) / 3โ(3ร3) = ๐โ
Simplifying:
2(2)โ3 / 3(3)โ1 = ๐โ
Finally:
4โ3 / 9 = ๐โ
Now, we can substitute the values of ๐โ and ๐ into the formula for the G.P to find the 1st, 4th, and 7th terms:
To find the 1st term:
๐โ = 4โ3 / 9
To find the 4th term:
๐โ = (4โ3 / 9) ร ๐ยณ
To find the 7th term:
๐โ = (4โ3 / 9) ร ๐โถ
Substituting the value of ๐ (โ3/โ4) into the above equations will give you the final values of ๐โ, ๐โ, and ๐โ.