Consider this:
let y = x^2 - 4x - 5, so
dy/dx = 2x - 4.
At any turning point, dy/dx = 0, so
2x - 4 = 0, so
x = 2.
When x = 2,
y = 2^2 -8 -5,
y = 4 - 8 - 5
y = -9.
d^2y/dx^2 = 2, so the turning point is a minimum.
Hence the turning point of y = x^2-4x-5 is (2, -9)
Hope this helps, Twiggy.
2007-09-07 08:11:07
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answer #1
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answered by Twiggy 7
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f(x)=x^2-4x-5
x- c00rdinate of vertex is -b/2a = 4/2=2
y-coordinate is 2^2-4*2-5 = -9
So vertex is (2,-9) which is the turning point
2007-09-07 14:52:19
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answer #3
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answered by ironduke8159 7
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