Find 
by using the Chain Rule. Express your final answer in terms of t.w = ex cos y + ey cos x; x = 9t, y = -4t
A. e-4t(9 cos -4t + 4 sin -4t) e9t(-4 cos 9t - 9 sin 9t)
B. e9t(9 cos -4t + 4 sin -4t) e-4t(-4 cos 9t - 9 sin 9t)
C. e-4t(9 cos -4t - 4 sin -4t) e9t(-4 cos 9t + 9 sin 9t)
D. e9t(9 cos -4t - 4 sin -4t) e-4t(-4 cos 9t + 9 sin 9t)
Answer: B
Mathematics
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Solve the problem.Find the number of units that must be produced and sold in order to yield the maximum profit, given the following equations for revenue and cost:R
= 5xC
= 0.01x2 + 0.7x + 40.
A. 285 units B. 215 units C. 430 units D. 570 units
Mathematics
Write the quotient in the form a + bi.
A. 
+ 
i
B. 
- 
i
C. 
- 
i
D. 
- 
i
Mathematics
Find the mean of the set of data. Round to the nearest tenth.3, 11, 4, 3, 3, 4, 4, 4, 4, 11, 4, 11, 4
A. 5.3 B. 6.4 C. 5.4 D. 4.9
Mathematics
Add. Simplify, if possible.-4 + (-1)
A. 3 B. -5 C. -3 D. 5
Mathematics