Find the exact value by using a half-angle identity.cos 165°
A. - 
B. 
C. 
D. - 
Answer: D
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Find the unit tangent vector T and the principal unit normal vector N. r(t) = (6t sin t + 6cos t)i + (6t cos t - 6 sin t)j - 6k
A. T = (cos t)i - (sin t)j; N = (-sin t)i - (cos t)j B. T = (cos t)i + (sin t)j; N = (-sin t)i + (cos t)j C. T = (-cos t)i - (sin t)j; N = (sin t)i + (cos t)j D. T = (-cos t)i - (sin t)j; N = (sin t)i - (cos t)j
Solve the problem.The inequality |T - 9| ? 17 describes the range of monthly average temperatures T in degrees Fahrenheit at a City X. (i) Solve the inequality. (ii) If the high and low monthly average temperatures satisfy equality, interpret the inequality.
A. 26 ? T ? 43; The monthly averages are always within 
B. -16 ? T ? 34; The monthly averages are always within 
C. -8 ? T ? 26; The monthly averages are always within 
D. 34 ? T ? 59; The monthly averages are always within 
Write the phrase as a mathematical expression. Use x to represent the number. Combine like terms if possible.6 times a number added to -8, added to 6 times the sum of 9 times the number 
A. 6x - 8 + 6(9 + 7x); 48x + 60 B. 6(-8 + x) + 6(9x + 7); 60x - 41 C. 6(9x + 7) + [6x + (-8)]; 60x + 34 D. 6(-8 + x) + 6(9 + 7x); 13x + 6
Simplify. Write your answer with positive exponents only.
A. 
B. 
C. 
D. 8x - 24y2