Question

If an A. P. d=-4 then t20-t15



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Answer 1

Answer:

the given sequence an AP? If yes, then find common difference: `2,5/2,3,7/3,…

Answer 2

Answer:

If an A. P. d=-4 then T₂₀ - T₁₅ = - 20.

Step-by-step explanation:

Given: Common difference(d) = - 4.

Formula : Tₙ = a + (n - 1)d.

Using this formula in the equation, we get.

Find : T₂₀ - T₁₅

By using formula

T₂₀ = a + (20 - 1)d.

T₂₀ = a + 19d ------- (1)

and T₁₅ = a + (15 - 1)d.

T₁₅ = a + 14d -------(2)

From (1) and (2)

T₂₀ - T₁₅  = (a + 19d) - (a + 14d)

=a + 19d - a - 14d

= 19d - 14d

= 5d

Put the value of d

T₂₀ - T₁₅ = 5 x (- 4) = - 20.

So,T₂₀ - T₁₅ = - 20.