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# Hard vector question! watch

1. Find coordinates where line through (-5,-1) in the direction (2/3) (this is the direction vector) meets circle at x^2 + y^2 = 65?

I'll tag Zacken
2. (Original post by mil88)
Find coordinates where line through (-5,-1) in the direction (2/3) (this is the direction vector) meets circle at x^2 + y^2 = 65?

I'll tag Zacken
Conver the line into cartesian form y = mx + c and then plug it into the circle equation to get a quadratic in x.

What does the direction vector mean and how does it relate to the gradient of a line...? Think about it a bit.
3. (Original post by Zacken)
Conver the line into cartesian form y = mx + c and then plug it into the circle equation to get a quadratic in x.

What does the direction vector mean and how does it relate to the gradient of a line...? Think about it a bit.
Oh snap, I did exactly what you said before, but I wrote gradient to be 2/3 rather than 3/2 ! Hence, I got incorrect values.

By the way, can you actually work it out using vectors, or do you have to convert it to y= mx + c?
4. (Original post by mil88)
Oh snap, I did exactly what you said before, but I wrote gradient to be 2/3 rather than 3/2 ! Hence, I got incorrect values.

By the way, can you actually work it out using vectors, or do you have to convert it to y= mx + c?
You probably could in some perverted non A-Level way. Pretty sure you should convert it to y = mx + c.

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