Question

Let f(x) = (x–4) (x–5) (x–6) (x–7) then

• A. f '(x) = 0 has 4 roots
• B. f '(x) = 0 has 3 roots in (4,5)$\cup$ (5,6)$\cup$ (6,7)
• C. f '(x) = 0 has only one real root
• D. f '(x) = 0 has 3 roots in (3,4)$\cup$ (4,5)$\cup$ (5,6)

Answer 1

Answer: (B)

f '(x) = 0 has 3 roots in (4,5)$\cup$ (5,6)$\cup$ (6,7)

Answer 2

f(x) = (x– 4) (x–5) (x–6) (x–7)

Ž f '(x) = 0 has 4 roots in (4,5)$\cup$ (5,6)$\cup$ (6,7)