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DNA : 7th September'2019 - Part 3
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This lesson deals with the Part 3 of the Daily News Analysis of 7th September 2019

Ajay Kumar Muchakurthi is teaching live on Unacademy Plus

Ajay Kumar Muchakurthi
Plus Educator, Expertise in Current Affairs, Governance, Science and Technology, Internal Security & Disaster Management

Unacademy user
hllo mam can u explain how u used dat formula in q6 n(n-1)+n(n+1)......=b
Binati Sheth
a year ago
Consecutive numbers as in numbers that come next to each other in order like 11, 12, 13. Now I can assume x = 11, so 12 = x+1, 13 = x+2.... I can also assume x= 12 so, 11=x-1 and 13 = x+1.... So, to make things simpler as in to get + and - x and 1, we generally assume consecutive numbers as ...x-2, x-1, x, x+1, x+2... Here, our roots are consecutive. Let the roots be x-1, x, x+1... so, with powers of 3, ax3 + bx2 + cx + d = 0, sum of roots = (x-1+x+x+1)= -b/a..... product of roots = (x-1)(x+1)x = -d/a..... and sum of products = (x-1)x + (x-1)(x+1) + (x+1)x = c/a....... Insert these values in our question and you'll get the equation