Another Question (1 Viewer)

[mike12345678]

i) find in exact form the tan of tha acute angle between the lines root3 +y-2=0 and the line y=x+1.

ii) hence show that the exact value of tan is 75 degrees is 2+root3

thanx again
i can do the second part easily but want to see how to use part i) to do part ii)

 

[interesting]

Editing..

 

[D94]

You need to use the "angle between two lines" formula:



Find the gradient of the two lines and sub them into the formula.


Edit: I thought that was a root3 x.... if it isn't, then it's a zero gradient for the first equation.

 

[FTW]

i) find in exact form the tan of tha acute angle between the lines root3 +y-2=0 and the line y=x+1.

ii) hence show that the exact value of tan is 75 degrees is 2+root3

thanx again
i can do the second part easily but want to see how to use part i) to do part ii)

How could you do the second part "easily" if the question was HENCE. That means you HAVE to use part 1 answer...

 

[mike12345678]

[QUOTE Editing..[/QUOTE]
yea i forgot a part of the question ii)

yea i tried the formula but i dont seem to get the right answer

 

[D94]

yea i tried the formula but i dont seem to get the right answer

You break up tan(75) into tan(45+30) and apply the tan formula for angles results.

The formula is:

 

[interesting]

GRADIENT FOR root3 +y-2=0 is 0

GRADIENT FOR y=x+1 is 1


i. So using theangle between 2 lines formula:









so now we know that tan45 = 1 which we will substitute in the next question



ii. We can split up tan75 into tan(30+45) by using the compound formula:






(sub in 1 for every tan 45 because this is what you got in i.)




(Rationalize)

 

[b3kh1t]

Find the gradients of and .

Using the general form y=mx+b, where m is the gradient. Therefore the gradients for the equations are 0 and 1 respectively.

substitute this into the formula

you get





That's for the first questions

 

[bleakarcher]

ur not really using the result from part i). that question was shit

 

[interesting]

ur not really using the result from part i). that question was shit

yes you are .. part 1 shows that tan 45 = 1 which is used to substitute into part 2 which involves tan 45's

 

[D94]

yes you are .. part 1 shows that tan 45 = 1 which is used to substitute into part 2 which involves tan 45's

Yes and no. Yes, because of your reason. No, because you didn't need to derive the first part to answer the second, ie. you can simply split 75 into 45 and 30, and those two results have pre-determined exact forms. Though, it would have been better to have something like 15 and 60, as 15 is a little more ambiguous.

 

[interesting]

Yes and no. Yes, because of your reason. No, because you didn't need to derive the first part to answer the second, ie. you can simply split 75 into 45 and 30, and those two results have pre-determined exact forms. Though, it would have been better to have something like 15 and 60, as 15 is a little more ambiguous.

maybe this question was like REALLY SIMPLE or something.. like to help you remember that tan 45 = 1 but that's the only way i can think of linking these parts. What do you suggest?

 

[bleakarcher]

in ur working i) and ii) dont really relate so next time stfu, haa?

 

[interesting]

in ur working i) and ii) dont really relate so next time stfu, haa?

you're the one complaining that the question was shit so why don't you stfu

 

[bleakarcher]

that question was shit not hard, the answer i knew how to derive almost immediately as i stared upon it

 

[hup]

that question was shit not hard, the answer i knew how to derive almost immediately as i stared upon it

do you have anger problems

 

[SpiralFlex]

Also guys, if you were in my school. You would all be wrong. This question was taken from the Independent paper and I recall the teacher strictly rambling on you must graphically show the information since it is a "hence" question. Back to the HSC now, peace.