Can anybody show me how to do this half angle identity problem step by step? i always seem to be missing something

Step-by-step explanation:

It is given that θ is between 270° and 360°, which means that θ is located in Quadrant IV ⇒ (x > 0, y < 0).  Furthermore, the half-angle will be between 135° and 180°, which means the half-angle is in Quadrant II ⇒

It is given that sin θ =  ⇒  y = -7 & hyp = 25

Use Pythagorean Theorem to find "x":

x² + y² = hyp²

x² + (-7)² = 25²

x² + 49 = 625

x²         = 576

      x   =  24    

Use the "x" and "hyp" values to find cos θ:

Lastly, input cos θ into the half angle formula:

Reminder: We previously determined that the half-angle will be negative.

no

Step-by-step explanation:

Establish the nth term formula

There is a common difference d between consecutive terms, that is

d = - 5 - (- 9) = - 1 - (- 5) = 3 - (- 1) = 7 - 3 = 4

This indicates the sequence is arithmetic with nth term

= a₁ + (n - 1)d

where a₁ is the first term and d the common difference

Here a₁ = - 9 and d = 4 , then

= - 9 + 4(n - 1) = - 9 + 4n - 4 = 4n - 13

Equate 4n - 13 to 301

4n - 13 = 301 ( add 13 to both sides )

4n = 314 ( divide both sides by 4 )

n = 78.5

Since n is not an integer then 301 is not in the sequence