Question

PLEASE HELPPP MEEE PLEASEE!!!

Answer 1

Step-by-step explanation:

17)

sec(x) = 1/cos(x)

cot(x) = cos(x)/sin(x)

so,

cos(x)/sin(x) × 1/cos(x) = 1/sin(x) = csc(x)

18)

2×sin(x) + 1 = 0

2×sin(x) = -1

sin(x) = -1/2 = -0.5

x = 210° or x = 330°

why ? sin(30°) = 0.5

so, sin(x) = -0.5 means the angles in the 3rd and 4th quadrant (where sine points "down" and is therefore negative). and x is then either 30° more than 180° (210°) or 30° less than 360° (330°).

draw a circle with the coordinate axis through the center. and then try and see.

19)

again the law of sine :

a/sin(A) = b/sin(B) = c/sin(C)

where the sides (a, b, c) are always opposite to the correlated angles (A, B, C).

so, in our case we have

8/sin(A) = 10/sin(58)

sin(A) = 8×sin(58)/10 = 0.678438477...

A = 42.7217403...° ≈ 43°

20)

so, we have 2 sides and the enclosed angle.

the area of the triangle in this case is

1/2 × a×c×sin(B) = 1/2 × 12×8×sin(60) = 48×sin(60) =

= 41.56921938... ≈ 42