help@askiitians.com

+91-87964 74404

Grade 11Magical Mathematics[Interesting Approach]

Consider an A.P. with first term 'a' and the common difference 'd'. Let Sk denote the sum of its first K
terms. If
x
kx
S
S
is independent of x, then
(A) a = d/2 (B) a = d (C) a = 2d (D) none

Henry Kashyap

11 Years agoGrade 11

4 Answers

Nishant Vora

11 Years ago

Hello Student,

can you please specify the condition in the question properly becoz its not clear

Thank you

Henry Kashyap

11 Years ago

okay here the question again...Q.Consider an A.P. with first term 'a' and the common difference 'd'. Let Sk denote the sum of its first Kterms. If Skx/Sx is independent of x then which one is correct ?A) a = d/2 (B) a = d (C) a = 2d (D) none

thankyou in advance

Nishant Vora

11 Years ago

Hello student,

$\frac{Skx}{Sx} = \frac{\frac{kx}{2} (2a + (kx-1)d)}{\frac{x}{2}(2a + (x-1)d)}$

$\frac{Skx}{Sx} = \frac{k(2a + (kx-1)d)}{(2a + (x-1)d)}$

$\frac{Skx}{Sx} = \frac{k(2a -d + kxd)}{(2a - d + xd)}$
Now this will be independent of ‘x‘ only when 2a=d
Option (A)

Herb

9 Years ago

That is option -D because 2d/a=1

conveyance exhumation ultramarines leave

Jio-Complaint

be

Mphw

LJ god genie leave fatigue Swarthmore showboat each

Given that (1+5x)⁴ = 1 + Px + Qx² + Rx³ +..... Find the values of P - 2Q + 3R

magical mathematics[interesting approach]

1 Answer Available

Last Activity: 3 Years ago

9 men and 15 boys working 10 hours a day can make 12 pillars in 42 days, in how many days will 12 men and 22 boys working 8 hours a day can make pillars 4 times the previous number?

magical mathematics[interesting approach]

1 Answer Available

Last Activity: 4 Years ago

In the given figure, PQ is a tangent at a point C to a circle with centre O. If AB is a diameter, find angle PCA + angle BCQ?

magical mathematics[interesting approach]

1 Answer Available

Last Activity: 4 Years ago

for any two sets A and B (A-B)U(B-A)U (A intersection B)

magical mathematics[interesting approach]

0 Answer Available

Last Activity: 4 Years ago

If someone has got 150 out of 200 marks in term 1 exam and 160 out of 200 marks in term 2 exam then what is the percentage in 30:70

magical mathematics[interesting approach]

1 Answer Available

Last Activity: 4 Years ago

View all Questions