Answer:
= 5n - 2
Step-by-step explanation:
the nth term of an arithmetic sequence is
= a₁ + (n - 1)d
where a₁ is the first term and d the common difference
given a₄ = 18 and a₁₀ = 48 , then
a₁ + 3d = 18 → (1)
a₁ + 9d = 48 → (2)
subtract (1) from (2) term by term to eliminate a₁
6d = 30 ( divide both sides by 6 )
d = 5
substitute d = 5 into (1) and solve for a₁
a₁ + 3(5) = 18
a₁ + 15 = 18 ( subtract 15 from both sides )
a₁ = 3
Then
= 3 + 5(n - 1) = 3 + 5n - 5 = 5n - 2
Answer:
The cost of painting the hemispherical dome is 110880 unit
Step-by-step explanation:
Given as for a hemispherical dome :
The circumference of base = 17.6 m
The cost of painting it = 5 unit per 100 cm²
∵ circumference of base = circumference of circle = 2××radius
So ,17.6 m = 2××radius
Or, Radius =
Or, Radius = = 2.8 m
Or, R = 280 cm
So, Total surface area of hemispherical dome = 3××radius²
or, Total surface area of hemispherical dome = 3××280²
Or, Total surface area of hemispherical dome =
Or, Total surface area of hemispherical dome =
∴ Total surface area of hemispherical dome = 739200 cm²
Now, The cost of painting 100 cm² is 15 unit
So, The cost of painting 739200 cm² =
Or, The cost of painting 739200 cm² = 110880 unit
Hence The cost of painting the hemispherical dome is 110880 unit Answer