Manipal MET2014MathematicsApplication of Derivatives
The largest term in the sequence a_n= n^2 n^3+200 is given by
Options
- A529 49
- B8 89
- C49 543
- DNone of these
Correct answer
C. 49 543
Step-by-step solution
Consider the function f(x)= x^2 x^3+200 aligned & & f^ (x) & =x (400-x^3 ) (x^3+200 )^2 =0 & & x^3 & =400 & & x & =(400)^ 1 / 3 aligned When x 0, f^ (x) 0x 0, f^ (x) 0 f(x) has maximum at x=(400)^ 1 / 3 Since, 7 (400)^ 1 / 3 8 , either a₇ or a₈ is the greatest term of the sequence. a₇= 49 543 , a₈= 8 89 and 49 543 8 89 a₇= 49 543 is the greatest.