# Precalculus

posted by Anonymous

I did these problems by drawing a graph ... So it would be great if you do it that way too if you need to correct me.
I know this is overwhelming but please take your time... It is easier for me to post all of these at once,since I can find it easier rather than posting many posts...

1. 11 units at 0 degree followed by 5 units along a bearing of 70 degrees
My answer: 13.6 units at 20.1 degrees
2. 8 units at 90 degrees followed by 6 units along a bearing of 210 degrees
My answer: 7.21 units at 136 degrees
3. 6 units at 270 degrees followed by 14 units along a bearing of 110 degrees
My answer: 8.61 units I DO NOT UNDERSTAND HOW TO FIND THE ANGLE BECAUSE WHEN I USED THE LAW OF COSINES I GOT 146 DEGREES...SO AM I SUPPOSED TO DO THIS??: 180-146= acute angle....BUT THEN I DON'T GET WHICH DIRECTION SHOULD I ADD UP THE ANGLE THAT SMOOCHES AT THE RESULTANT VECTOR... IN OTHER WORDS, WHEN STARTING ON THE Y AXIS OR THE NORTH POSITION DO I GO RIGHT OR LEFT AND WHY??????????
4. 4 units at 180 degrees followed by 9 units along a bearing of 320 degrees
My answer: 6.47 units at 243 degrees
5. A ship sails 50 mi on a bearing of 20 degrees and then 30 mi further on a bearing of 80 degrees . Find the resultant displacement vector as a distance and bearing.
My answer : 70 miles at 41.8 degrees
6. A plane flies 200 mi/hr along a bearing if 320 degrees. The air is moving with a speed of 60 mi/hr along a bearing of 190 degrees.
My answer: 168 mi/hr at 304 degrees
7. A scuba diver swims 100 ft/min along a bearing of 170 degrees. The water is moving with a current of 30 ft/min along a bearing of 115 degrees.
My answer: 116 ft/min at 156.5 degrees
8. Given: 120 yards at 80 degrees and 22 yards at 10 degrees
My answer: 129 yards at 70.8 degrees

1. Steve

first off, you move along a heading.
If you see something and determine its position, then the bearing is the direction from where you are.
Now on to the calculations.

#1. ok
#2. ok
#3. I do mine by converting each position to rectangular coordinates, then adding the vectors, then converting back to polar coordinates. Keeping in mind that a compass heading of x° is a polar angle of (90-x)°
So, for this one, I do
6@270° = -6,0
14 @ 110° = 13.16,-4.79
add them up to get 7.16,-4.79
d = 8.61
θ = -33.8
Using the law of cosines does get tricky.
#4. I get 6.47 at 296.6°
#5. I get 32.8 at 72.4°
#6. ok
#7. ok
#8. ok

## Similar Questions

1. ### extreme value of absolute.....

find the extreme values of the function on the interval and where they occur. f(x) = |x-1|-|x-5|, -2<=x<=7 How do I do this?
2. ### Functions

I need help with the following problems please?
3. ### English: final revision - Ms. Sue

Thesis: The pathetic and alarming need for education of HIV/AIDS in Africa is overwhelming and the great need is to protect and educate people to reduce the disease. The author uses his wisdom to research statistics that are so compelling; …

This is the question I posted about two hours ago and I worked it out two ways-could you scroll down and check it, please?

This is the question I posted about two hours ago and I worked it out two ways-could you scroll down and check it, please?
6. ### Physics

posted this question this morning but I'm not sure of the response Damon provided. I did it once but then I updated it later in this at the bottom- please check booth of my answers. If you were in a rotor style ride and the riders …