Solve the problem.The minimum length L of a highway sag curve can be computed by  where ?1 is the downhill grade in degrees (?1< 0°), ?2 is the uphill grade in degrees (?2> 0°), S is the safe stopping distance for a given speed limit, h is the height of the headlights, and ? is the alignment of the headlights in degrees. Compute L for a 55-mph speed limit, where   

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A. 597 ft

B. 565 ft

C. 551 ft

D. 581 ft

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Answer: B

Mathematics

Use a calculator to find the approximate value of the expression. Round the answer to two decimal places.tan 72°

A. -0.33 B. 3.01 C. 3.08 D. -0.26

Factor the expression. Express your answer so that only positive exponents occur. x6/7 + 3x2/7

A. x2/7(x-4/7 + 3) B. x1/7(x6/7 + 3) C. x1/7(x4/7 + 3) D. x2/7(x4/7 + 3)

Find the derivative of f at x. That is, find f '(x).f(x) = ; x = 3

A. - 
B.
C. - 
D.

Write the expression as the sum or difference of logarithms.logb 

A. logb m2 + logb (m - n)3  B. 2logb m - 3logb (m - n) C. 2logb m + 3logb (m - n) D. m2 - (m - n)3