Respuesta :
Let f(x) be the given function.
Answer is a and d, because f(-2)<0 and f(-1)>0; and f(1)<0 and f(2)>0, so there is a change of sign, signifying that between the limits there is a value of x where f(x) must be 0 (the curve crosses the x axis).
Answer:
Options a. and d. are correct
Step-by-step explanation:
Intermediate Value Theorem:
Let f be a continuous function on [tex]\left [ a,b \right ][/tex] such that for a number p, [tex]f(a)<p<f(b)[/tex] then there exists q in [tex]\left ( a,b \right )[/tex] such that f(p) = q
Let f(x) = [tex]x^4 - 2x^2 - 1[/tex]
For a. [-2,-1] :
f(-2)=7>0 and f(-1) = -2 < 0 such that f(-1) < 0 < f(-2) then as per the theorem, there exists a number c in (-2,-1) such that f(c) = 0
For d. [1,2]:
f(1)= - 2<0 and f(2) = 7 > 0 such that f(1) < 0 < f(2) then as per the theorem, there exists a number c in (1,2) such that f(c) = 0
So, options a. and d. are correct