• Best of luck to the class of 2024 for their HSC exams. You got this!
    Let us know your thoughts on the HSC exams here
  • YOU can help the next generation of students in the community!
    Share your trial papers and notes on our Notes & Resources page
MedVision ad

Coordinate geo question once again ! (1 Viewer)

Aysce

Well-Known Member
Joined
Jun 24, 2011
Messages
2,394
Gender
Male
HSC
2012
Hey guys the question is :

Find the acute angle between the lines and
Originally I received the angle of 60 degrees, but in the answers it says 30 degrees.

Please check if my answer is right, if not please justify why thanks ! :awesome:
 

slyhunter

Retired
Joined
May 17, 2009
Messages
6,803
Gender
Male
HSC
2011
It's 30.

Edit: read it as y=3 instead of x=3 >_>

Sorry OE :)
 
Last edited:

Aysce

Well-Known Member
Joined
Jun 24, 2011
Messages
2,394
Gender
Male
HSC
2012
Can someone work it out, because wouldn't the gradient of x =3 be 0? Full working pl0x
 

hscishard

Active Member
Joined
Aug 4, 2009
Messages
2,033
Location
study room...maybe
Gender
Male
HSC
2011
1.Sketch the situation
2.Actually sketch the situation
3.Check if you've drawn it correctly

gradient of x=3 is clearly undefined as rise is like infinity and run = 0.
However, if you sketched everything, you'll see that x=3 makes right angles with the x axis. Gradient of y=root3x = root3. angle between line and x axis = 60. 90-60 = 30

say it was y=3 instead, y=3 has a gradient of 0. Then the angle between the two lines will be just 60. In this case you could've used the tan expansion to find the angle
 

Aysce

Well-Known Member
Joined
Jun 24, 2011
Messages
2,394
Gender
Male
HSC
2012
1.Sketch the situation
2.Actually sketch the situation
3.Check if you've drawn it correctly

gradient of x=3 is clearly undefined as rise is like infinity and run = 0.
However, if you sketched everything, you'll see that x=3 makes right angles with the x axis. Gradient of y=root3x = root3. angle between line and x axis = 60. 90-60 = 30

say it was y=3 instead, y=3 has a gradient of 0. Then the angle between the two lines will be just 60. In this case you could've used the tan expansion to find the angle
Thanks a lot! I understand now :)
 

Drongoski

Well-Known Member
Joined
Feb 22, 2009
Messages
4,255
Gender
Male
HSC
N/A
Surprised this generated so much exchange - it's 30 deg indeed. The 1st line makes 60 deg with the positive x-axis and x=2 makes 90 deg.
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top