Webn(2a+(n−1)d). Key Point The sum of the terms of an arithmetic progression gives an arithmetic series. If the starting value is a and the common difference is d then the sum of the first n terms is S n = 1 2 n(2a+(n−1)d). If we know the value of the last term ℓ instead of the common difference d then we can write the sum as S n = 1 2 n ... WebIn an AP, if the common difference (d) = –4, and the seventh term (a 7) is 4, then find the first term. Advertisement Remove all ads Solution n th term of an AP is T n =a+ (n−1)d For an AP with the first term as 'a' and common difference as 'd', the seventh term is a + 6d.
Nth Term Of A Sequence - GCSE Maths - Steps, Examples
WebMohammed Owais. 2 years ago. Its bcoz, (Ref=n/2) the sum of any 2 terms of an AP is divided by 2 gets it middle number. example, 3+6/2 is 4.5 which is the middle of these terms and if you multiply 4.5x2 then u will get 9! ( 1 vote) WebCorrect option is C) As we know nth term, a n=a+(n−1)d & Sum of first n terms, S n= 2n(2a+(n−1)d), where a & d are the first term amd common difference of an AP. Given, a=5,d=3,a n=50 ⇒a+(n−1)d=50 ⇒5+(n−1)3=50 ⇒5+3n−3=50⇒3n=48⇒n=16 ∴S 16= 216[2a+(16−1)d]=8[2×5+15×3]=440 Hence, n=16,S 16=440 Solve any question of … order model of managing client requirement
In an AP, if d = -4, n = 7, an = 4, then a is, a. 6, b. 7, c. 20, d. 28
WebThe nth term of an AP is (7 - 4n). Find its common difference. Solution Given the nth term is 7 - 4n an= 7−4n Put n = 1, a1= 7−4×1 =7−4 =3 Put n = 2, a2= 7−4×2 =7−8 =−1 Common difference d=a2−a1 = −1−3= −4 So common difference of the AP is -4 Suggest Corrections 51 Similar questions Q. The nth term of an AP is (7 − 4n). Find its common difference. WebIn the given AP, the first term is a = 7 and the common difference is d = 4. Let us assume that 301 is the n th term of AP. Then: T n = a + (n - 1)d 301 = 7 + (n - 1) 4 301 = 7 + 4n - 4 … WebIn an AP, if d = - 4 , n = 7 and an = 4, then a is equal to A) 6 B) 7 C) 20 D) 28 Solution I n an AP, an =a+(n−1)d ⇒ 4= a+(7−1)(−4) [by given conditions] ⇒ 4= a+6(−4) ⇒ 4+24= a ∴ a= 28 … order modification navy