Find cos8 pi3 A 16 B 13 C 12 D Squareroot 32 F Squareroot 22

Find cos(8 pi/3). (A) 1/6; (B) 1/3; (C) 1/2; (D) Squareroot 3/2; (F) -Squareroot 2/2; (G) 0; (H) -1/2 Find cos^-1 (sin(pi/6)). (A) pi/6; (B) -pi/6; (C) pi/4; (D) - pi/4; (E) -pi/3; (F) - pi/3; (G) 0 Find all solutions of cos(theta) = -Squareroot 3/2 in the interval [0 degree, 360 degree]. (A) 60 degree, -60 degree; (B) 60 degree; 300 degree; (C) 30 degree 240 degree; (D) 210 degree, 330 degree; (E) 150 degree, 210 degree; (F) 30 degree, 330 degree Find the exact value of cos(pi/4 - pi/3). (A) Squareroot 3 + Squareroot 6/4; (B) Squareroot 2 - Squareroot 6/4; (C) Squareroot 6 - Squareroot 2/4; (D) - Squareroot 2 - Squareroot 6/4; (E) Squareroot 2 + Squareroot 6/2 Find cos^-1 (cos(7 pi/6)). (A) pi/6; (B) -pi/6; (C) 5 pi/6; (D) -5 pi/6; (E) -7 pi/6; (G) 0 For problem 20 consider a triangle with angles A, B, C and sides a, b, c where side a is opposite to angle A, side b is opposite to angle B, and side c is opposite to angle C. If angles A = 125 degree, C = 35 degree, and side c = 26 ft, find angle c = 26 ft, find angle B and sides a, b. Answers: angle B =, side a = ft, side b = ft If 2i/Squareroot 3 is one solution of the equation 18x^4 + 21x^3 + 15x^2 + 28x - 12 = 0, find all solutions. Answer: x = 2t/Squareroot 3, and x =, and x =, and x =

Solution

13. Point is (1,-3)

     tan theta=y/x

tan theta = -3/1

Correct option is H

14. We have to use the following formula here

      A=P(1 + (r/n))^{n t}

   In this question P= $1756   , r=8%=.08 , t=14 yrs, n=4

A= 1756(1+(.08/4))^4*14   = 1756(1.02)⁵⁶    = $5323

15. cos (8pi/3) =   cos (3pi    - pi/3)

cos(3pi - theta) = -cos theta

Therefore cos(3pi - pi/3) =-cos(pi/3) =-1/2

Correct option is H