Determine whether each expression below is always, sometimes, or never equivalent to sin x when 0° < x < 90° ? Can someone help me :(

--- Never true

--- Always true

---- Sometimes true

---- Sometimes true

Step-by-step explanation:

Given

Required

Determine if the following expression is always, sometimes of never true

Expand using cosine rule

So, we have:

Hence: (a) is never true

Expand using cosine rule

So, we have:

Hence: (b) is always true

If

Then:

Divide both sides by 2

(c) is only true for

Hence: (c) is sometimes true

If

Then:

Divide both sides by 2

(d) is only true for

Hence: (d) is sometimes true

question: how many people can she serve?

answer: she can serve 16.66666667 people. so she can only give 16 people a complete serving.

question: does she have enough ice cream for her guests?

answer: no. explanation: she only has enough for 16 people to have a full serving. however, she can give a 17th person a partial serving.