Write the real form of each complex equation.
a. z = 4 cos(theta) + 9i sin(theta)
b. z = 6 cos(theta) + i sin(theta)
c. z = √5 cos(theta) + √10i sin(theta)
d. z = 5 − 2i + 4 cos(theta) + 7i sin(theta)

In trapezoid efgh, m∠hef=(4x2+16)∘ and m∠gfe=(5x2+12)∘. find the value of x so that efgh is isosceles.

Triangle xyz has vertices x(1,3), y(0,0)

The first-serve percentage of a tennis player in a match is normally distributed with a standard deviation of 4.3%. if a sample of 15 random matches of the player is taken, the mean first-serve percentage is found to be 26.4%. what is the margin of error of the sample mean? a. 0.086% b. 0.533% c. 1.11% d. 2.22%