Q23 of 102 Page 394

In an AP, it is being given that . Find .

To Find:

Given:

(Where T_n is nth term and d is common difference of given AP)

Formula Used: T_n = a + (n - 1)d

= (cross multiply)

3a + 9d = 2a + 12d a = 3d …….equation (i)

Now = = =

So =

How many 2 - digit numbers are divisible by 3?

If θ₁, θ₂, θ₃, …., θ_n are in AP whose common difference is d, show that

sec θ₁sec θ₂ + sec θ₂sec θ₃ + …. + sec θ_n–1sec θn = .

Three numbers are in AP. If their sum is 27 and their product is 648, find the numbers.

The sum of three consecutive terms of an AP is 21, and the sum of the squares of these terms is 165. Find these terms