Answer:
4. dy/dx = -2
8. dy/dx = 1/2 x^(-3/2)
10/ dy/dr = 4 pi r^2
Step-by-step explanation:
4. y = -2x+7
dy/dx = -2(1)
dy/dx = -2
8. y = 4 - x^-1/2
dy/dx = - (-1/2x^ (-1/2-1)
dy/dx = 1/2 x^(-3/2)
10. y = 4/3 pi r^3
dy/dr = 4/3 pi (3r^2)
dy/dr = 4 pi r^2
Lines are perpendicular if the slope of one is the negative reciprocal of the other. In this case the slopes are -8/3 and 8/3, so while negative they are not reciprocal. So no, the two lines intersect but are not perpendicular.
Let's say 1000 dollars was spent on all of these. That would mean 170 dollars and 240 were spent on food and entertainment respectivly. If we want to see how much of the total cost was spent on these things, we would have to add them and divide them by 1000, so:
