Suppose you are given the function f(x)=sinx+bcosx . Which of the following relationships will ensure that a local extremum occurs at x = k in the interval (0,π2) ? (1 point) Responses b=−2cotk b = − 2 cot k b=−cotk b = − cot k b=−tank b = − tan k b=cotk b = cot k b=tank b = tan k Question 2 Part B Which of the following relationships will ensure that an inflection point occurs at x = k in the interval (0,π2) ? (1 point) Responses b=−2cotk b = − 2 cot k b=−cotk b = − cot k b=−tank b = − tan k b=cotk b = cot k b=tank b = tan k Skip to navigation

1 answer

To find the local extremum of f(x), we need to find the critical points of f(x), which occur when f'(x) = 0.

f'(x) = cos(x) - bsin(x)

Setting f'(x) = 0, we have:

cos(x) - bsin(x) = 0

We can rewrite this equation as:

cos(x) = bsin(x)

Dividing both sides by cos(x), we get:

1 = btan(x)

Therefore, we have b = tan(x).

So, the correct relationship to ensure a local extremum at x = k is b = tan(k).

For the inflection point of f(x), we need to find where f''(x) = 0 or where the second derivative changes sign.

f''(x) = -sin(x) - bcos(x)

Setting f''(x) = 0, we have:

-sin(x) - bcos(x) = 0

We can rewrite this as:

sin(x) = -bcos(x)

Dividing both sides by cos(x), we get:

tan(x) = -b

Therefore, the correct relationship to ensure an inflection point at x = k is b = -tan(k).