East walker at 3 mi/hr
NE walker at 2 cos 45 mi/hr
East distance between = (3 -1.41)t = 1.59 t
North distance between = 1.41 t
h = hypotenuse = t sqrt(1.59^2 + 1.41^2)
= 2.13 t
now find dh/dt
dh/dt = 2.13 mi/hr
your work doesn't match the wording of the question.
Where does it mention a north-walking person? (your x)
There isn't even a right angled triangle
I drew a horizontal line to the east (to the right)
then from the same starting point a line at 45º to the other one (going north-east)
(make the horizontal a little longer, it represents 3 mph)
let the distance between their endpoints be x
let the time after they both leave be t hours.
then the 'going-east' line has length 3t
the 'north-east' line is 2t
by Cosine Law
x^2 = (3t)^2 + (2t)^2 - 2(3t)(2t)cos 45º
= 13t^2 - 12t^2cos45
= 13t^2 - 6√2 t^2
dx/dt = 26t - 12√2t
when t = 15 min = 1/4 hour
dx/dt = 26(1/4) - 12√2(1/4)
= 2.26 mph
thanx I thought I had to use the cosine law but I wasn't quite sure how to.
But how did you decide that the angle would be 45 degrees?
where does a direction of North-East go in relation to East ?
What is the angle between North and East?
calculus - Two people start from the same point. One walks east at 3 mi/h and ...
Calculus - Two people start from rest at the same point. One walks east at 3 mi/...
Related rates - Two people start from the same point. One walks east at 1 mi/h ...
Math - A man walks one mile east, then he walks one mile northeast and then he ...
Math (Trigonometry) - Jasper walks 2 km due east. He then turns and walks 3 km ...
physics - a woman walks 2 km due east and then walks 4 km in the direction 30 ...
maths - a hiker walk due east at 4km per hour and a second hiker starting from ...
physics - A person walks 37.0◦ north of east for 5.00 km. Another person ...
english - Break the shoes in thoroughly on short walks before going on an ...
Math - John walks 20km due east then turns 270 degrees anticlockwise and walks ...