how do I solve these questions? I have tried and tried. thank you

P

PeterJ

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Would you please look over my work. I am not confident about the 3rd answer at all! And,
of course not the 4th either. Thank you so much. My exam is in days and I need to understand
this type of question.
 

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PeterJ said:
Would you please look over my work. I am not confident about the 3rd answer at all! And,
of course not the 4th either. Thank you so much. My exam is in days and I need to understand
this type of question.
Click to expand...

Where are Q3 and Q4 that you refer to?
 
4 trig problems.

Harry_the_cat said:
Where are Q3 and Q4 that you refer to?
Click to expand...
Hi , Thanks for looking at this. I will attach again.
Would you be able to tell me if Q1andQ2 are right?
Thank you.
Peter
 

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please look at all 4 and correct my work if possible so i can learn this. thank you

I have submitted 2 sheets, with 4 questions, did you get them?
 
Can anyone help? asap? please!

Please see my 4 questions attached.


PeterJ said:
Hi , Thanks for looking at this. I will attach again.
Would you be able to tell me if Q1andQ2 are right?
Thank you.
Peter
Click to expand...
 
Trig gr. 10 ,4 questions

Please find the 4 questions attached.
I need help asap, is anyone there who can help me?


PeterJ said:
Hi , Thanks for looking at this. I will attach again.
Would you be able to tell me if Q1andQ2 are right?
Thank you.
Peter
Click to expand...
 
Please help with Q3 and Q4

Would someone kindly help me work through these 2 questions.
 

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For the first problem, your answer is not correct. I'd recommend going back to the drawing board, clearly labeling each side of the triangle before doing any calculation. Your calculations of side lengths AC and CD are correct, but after that, you have formulas defining the values of "a" and "d", but I haven't the slightest clue as to which sides they refer. From what I can tell, your basic process to solve this problem is was to use the law of sines to find side length BD, and then you used the law of cosines to find length CB. However, It seems as if you went wrong in this last step by applying the law of cosines to the entire large triangle, rather than to one of the smaller triangles.

For instance, the correct formula to apply the law of cosines would be: (CB)^2 = (BD)^2 + (CD)^2 - 2(BD)(CD) * cos(61). The incorrect formula that you used was: (CB)^2 = (BD)^2 + (AD)^2 - 2(BD)(AD) * cos(61). Do you see why the formula you used won't get you the right answer?
 
ksdhart2 said:
For the first problem, your answer is not correct. I'd recommend going back to the drawing board, clearly labeling each side of the triangle before doing any calculation. Your calculations of side lengths AC and CD are correct, but after that, you have formulas defining the values of "a" and "d", but I haven't the slightest clue as to which sides they refer. From what I can tell, your basic process to solve this problem is was to use the law of sines to find side length BD, and then you used the law of cosines to find length CB. However, It seems as if you went wrong in this last step by applying the law of cosines to the entire large triangle, rather than to one of the smaller triangles.

For instance, the correct formula to apply the law of cosines would be: (CB)^2 = (BD)^2 + (CD)^2 - 2(BD)(CD) * cos(61). The incorrect formula that you used was: (CB)^2 = (BD)^2 + (AD)^2 - 2(BD)(AD) * cos(61). Do you see why the formula you used won't get you the right answer?
Click to expand...

Yes....I get so confused by what to look for first and then should have labelled properly.
Can you help with the next ones? Maybe looking at the way you do them will help me understand the process/
 
PeterJ said:
Hi , Thanks for looking at this. I will attach again.
Would you be able to tell me if Q1andQ2 are right?
Thank you.
Peter
Click to expand...

In Q3 you need to assume that the cliff is vertical and the ground is level (not unreasonable assumptions). So Angle DBC and Angle DBA are right angles. Now give it a go.

In Q4 you are on the right track. So finish it off.
 
PeterJ said:
Would someone kindly help me work through these 2 questions.
Click to expand...
I replied on your other post but here it is again:
Q3. You need to assume that the cliff is vertical and the ground is flat. This means that Angle DBA and Angle DBC are right angles. Try it now.

Q4. So far so good. Find the length of the other two sides and then the required angle. (as you did in Q2)
 
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Wow, thank you so much. It is weird that for Q3 the 70 could be the angle of the
lower triangle. If 360 is ttl then the other angle would be 200 degrees? 70 + 90+ 200.
 
iCant get the length of the sides in Q1. I get angle 85degrees , and have all angles, but when I use law of sines, I get a negative answer. Please help.
 
Denis said:
Well, Harry_the_cat thinks it is:

...perhaps he needs more cat food :p
Click to expand...

Always!:evil:

The problem is in 3 dimensions not 2. If the 70 refers to an angle, it is in the triangle which is flat on the ground. The cliff is vertical. There is no "circle" at that point to get 360 degrees. You need to visualise the diagram correctly.

The 70 could refer to the length of AC. This makes it a much easier problem.

The diagram looks like a dog drew it!
 
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