Let S=(-1, ) and f : S R be defined as f(x)= -1x (et-1 )11(2t-1)5(t-2)7(t-3)12(2t-10)61dt, Let p= Sum of squares of the values of x, where f(x) attains local maxima on S, and q= Sum of the values of x, where f(x) attains local minima on S. Then, the value of p2+2q is .
Answer
27
Solution
f'(x)= (ex-1 )11(2x-1)5(x-2)7(x-3)12(2x-10)61
odd powers change sign at x=0, 12, 2, 5; even power at x=3 ⇒ no sign change
[figure]
+ - (max) at x=0, 2 ⇒ p=02+22=4
- + (min) at x= 12, 5 ⇒ q= 12+5= 112
p2+2q=16+11=27
Answer: 27