Question

Precalc help please? Cartesian and polar coordinate system?

Picture will be attached.

I kind of understand what the question is asking, but I don't get how to locate the point. Could someone please explain?

Answer 1

@jim_thompson5910 @amistre64 @satellite73 anyone?

Answer 2

This is a very strange coordinate system, but I think when they say (4,3,25,120), they mean x = 4 and y = 3

So you're starting at (0,0) and going 4 units to the right and 3 units up. In other words, 4*25 = 100 meters east and then 3*25 = 75 meters north from the starting point

Answer 3

Hmmm well my answer key says 75m east; 118.30m north :/

Answer 4

ok let me think it over

Answer 5

ok I figured it out

Answer 6

first you convert (r,theta) = (2,120) into rectangular form to get

x = r*cos(theta)
x = 2*cos(120)
x = -1


y = r*sin(theta)
y = 2*sin(120)
y = 1.73205080756888


So (r,theta) = (2,120) turns into (x,y) = (-1,1.73205080756888)

This means you go from (4,3) and you shift 1 unit to the left and 1.73205080756888 units up to get to (4-1, 3+1.73205080756888) = (3,4.73205080756888)


Then you scale by 25 since each sprinkler head is 25 meters apart

25*3 = 75
25*4.73205080756888 = 118.301270189221


So that explains how they got the answer of 75 meters east, 118.30 meters north

Answer 7

Wow! Perfect explanation, thank you so much! :)

Answer 8

you're welcome