Answer is due in 1 hour!

find an equation of the tangent line to the curve
y = 10x sin x
at the point (π/2, 5π).

 y = 10x * sin(x) 
y' = 10 * (x * cos(x) + sin(x)) 
x = pi/2 
y' = 10 * ((pi/2) * cos(pi/2) + sin(pi/2)) = 10 * ((pi/2) * 0 + 1) = 10 * 1 = 10 
y - 5pi = 10 * (x - (pi/2)) 
y - 5pi = 10x - 5pi 
y = 10x

Skew lines(segments) are lines(segments) in 3 dimensions that do not intersect the given segment and are not parallel to it.  ae, bf, eg, and fh are your skew segments.  i hope that : )