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# Last one watch

1. Can someone asnwer part ii of this question, i could do the area bit I think if only I could get the co-ordinates of point B.
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2. I get (-2, 3) but I'm not completely sure!

If tangent at B is perpendicular to tangent at A, that means the gradient of tangent B is -1/½ = -2

So now dy/dx of the curve = 1/2x - 1
equate this to -2 , so 1/2x -1 = -2 , x=-2 (i.e. x coordinate is -2)
i,e. the point on the tangent where m = -2
Then put -2 into equation of curve to get y = 3
So co ordinates of B are (-2,3)
3. (Original post by Abbas6)
I get (-2, 3) but I'm not completely sure!

If tangent at B is perpendicular to tangent at A, that means the gradient of tangent B is -1/½ = -2

So now dy/dx of the curve = 1/2x - 1
equate this to -2 , so 1/2x -1 = -2 , x=-2 (i.e. x coordinate is -2)
i,e. the point on the tangent where m = -2
Then put -2 into equation of curve to get y = 3
So co ordinates of B are (-2,3)
Yep, that's correct!

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