Let $I=\int\limits_a^b(x^4 -2x^2) dx$. The ordered pair (a, b) for which I attains the least value, is
Answer & explanation
Correct answer: option 3
Clearly, the absolute value of I represents the area bounded by the curve $y = x^4 -2x^2$ and x-axis. So, the value of I is least when $a=-\sqrt{2}$ and $b = \sqrt{2}$.
