Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
COMEDK2012MathematicsSequences and Series

If y= ⁻¹ ( 1 1+x+x² )+ ⁻¹ ( 1 x²+3 x+3 )+ ⁻¹ ( 1 x²+5 x+7 )+ + upto n terms then d y d x at x=0 and n=1 is equal to

Options

  1. A1 2
  2. B- 1 2
  3. C0
  4. D1 3

Correct answer

B. - 1 2

Step-by-step solution

We have, aligned &y= ⁻¹ ( 1 1+x(x+1) )+ & ⁻¹ ( 1 1+(x+2)(x+3) )+ & ⁻¹ ( 1 1+(x+1)(x+2) )+ &+ ⁻¹ ( 1 1+(x+n-1)(x+n) ) aligned When n=1 , then aligned y &= ⁻¹ ( 1 1+x(x+1) ) &= ⁻¹ ( (x+1)-x 1+x(x+1) ) y &= ⁻¹(x+1)- ⁻¹ x d y d x &= 1 1+(x+1)² - 1 1+x² . d y d x |_ x=0 &= 1 1+(0+1)² - 1 1+(0)² &= 1 1+1 - 1 1 = 1 2 -1=- 1 2 aligned

Practice Sequences and Series on Quantrex Academy →

More from Sequences and Series

Every term of a geometric progression is positive , and every term is the sum of the two preceding terms. Then the common ratio of the geometric progression is: 2026If k is the arithmetic mean of two given quantities and p, q are the geometric means between the same two quantities, then p^3 + q^3 is: 2026Let ' a ' and ' b ' be two numbers where a < b . The geometric mean of these numbers exceeds the smaller number by 12 and the arithmetic mean is smaller than the larger number by 2 2026The product of three numbers in geometric progression is 8 and the sum of the product of the numbers taken in pairs is 14. Find the numbers. 2026Let a₁, a₂, a₃, be a geometric progression of positive integers such that a₁ = 3 and a_ n+2 - 2a_n = a_ n+1 for all positive integers n . What is the value of a₁ + a₂ + a₃ + a₄ + a 2026The angles of a triangle are in A.P and the greatest angle is double the least angle, then sine of the third angle is 2026If we insert two numbers between 2 and 4 so that the resulting sequence is in G.P, then the inserted numbers in the order are 2026If S _ n =1^3+2^3+ . .+ n ^3 and T _ n =1+2+ . .+ n , then 2025 Full Sequences and Series list All COMEDK PYQs