Find the exact value of the expression.cos 40° cos 20° - sin 40° sin 20°

A.
B.
C.
D.


Answer: D

Mathematics

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The formula for an exponential function is , where t is measured in months.  Then the monthly percentage growth rate for y is ??

A. 1.08% B. 8% C. 0.08% D. 8.02%

Mathematics

Simplify the expression.j11

A. j B. 1 C. -1 D. -j

Mathematics

Find the measure of the dihedral angle indicated.The figure shown is a right prism whose bases are regular hexagons. Find the measure of the dihedral angle between each lateral face and a base.

A. 135° B. 60° C. 90° D. 120°

Mathematics

Solve. = 3

A. 20, 50 B. 50 C. 20 D. 20, 50, 0

Mathematics