Im failing.. please help me.. Consider the arithmetic sequence.

-9, -2, 5, 12, . . .

Given that the sequence is represented by the function f(n), what are the values of f(1) and the common difference?

A.
f(1) = -2
Common difference : -7
B.
f(1) = -2
Common difference : 7
C.
f(1) = -9
Common difference : 7
D.
f(1) = -9
Common difference : -7

step-by-step explanation:

a and d

7.9m and 4.3°

step-by-step explanation:

let east be +x and north be +y, x = distance * cos θ, y = distance * sin θ  

for 3.5 south, y = -3.5  

for 8.2, x = 8.2 * cos 30 and y = 8.2 * sin 30  

for 15 west, x = -15  

total x = 8.2 * cos 30 – 15 ≈ -7.9  

total y = -3.5 + 8.2 * sin 30 = 0.6  

magnitude = [(8.2 * cos 30 – 15)^2 + 0.6^2)]^0.5  

the magnitude is approximately 7.9 m  

tan θ = y/x = 0.6/-7.9  

the angle is approximately 4.3˚ north of west

hd extra 3-7 x d en is the answer