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4 answers

Hope this is fast enough.
The gradient of the curve is found using differentiation. For this method, you need to know the equation of the curve in the form of y= ax^2+bx+c (where a b and c are real numbers, can be integers or fractions) and the x values of that point which you want to find the gradient of.
If the equation is something like y=(x+2)(x+5)
expand the equation to y=x^2+7x+5 to make it easier to solve

You differentiate the individual terms of the curve i.e. ax^2 become (2)ax or 2*a*x
you keep the coefficient (the coefficient of 2x is 2), bring down the power and reduce the power by 1 (so its become 2 to 1).
Another example 4x^3 is differentiated to (3)(4)x^2 = 12x^2
_dy_
..dx denotes differentiation of the expression y (y=ax^2+bx+c) with respect to x.
The constant (c) is omitted as the power of the constant is 0 ie 5 = (5)x^0
so the equation y=ax^2+bx+c is differentiated to
_dy_
..dx = (2)ax +b (bx become be as the power of x is 1) and c is omitted.

eg. 2x^2+3x+5 is differentiated to 4x+3
Now, you sub (i.e. substitue) the value of x of the point on the curve you want the gradient for e.g. x=3 so...
_dy_
..dx = (2)ax +b becomes (2)(a)(3) +b = 6a+b

for the exmaple 2x^2+3x+5 is differentiated to 4x+3
if x=3 for the point, u sub x=3 into 4x+3 which equals to
= 4(3)+3
=15

One last example
let's say the question is to find the gradient of the curve at point G (5,7) when the equation of the curve is y=(-x+3)(x-1)
you expand the Eqn so it becomes y= -x^2 + 2x - 3
This is differentiated to -(2)x +2
You sub in the value x=5 [which is from G in the form of (x,y)]
so the gradient of point g on the curve is
-(2)(5) +2
= -10+2
=-8
Hope this is comprehensive enough, and easy to understand. I tried to give as many examples as possible.

2007-03-09 04:24:26 · answer #1 · answered by hoxyho 2 · 0 0

differrentiate the equation of the curve . that is find the dy/dx of the equation. then substitute the given value of x.
good luck

2007-03-09 13:00:11 · answer #2 · answered by tomzy 2 · 0 0

If you have a function w=f(x,y,z) the gradient is
G = df/dx*i+df/dy*j +df/dz*k where df/d-are the partial derivatives of f and i,j,k the unit vectors alon the x,y and z axis respectivly

2007-03-09 12:14:18 · answer #3 · answered by santmann2002 7 · 0 0

Just get the derivative of the curve's function!!!!

GOOD LUCK!!!

2007-03-09 12:13:33 · answer #4 · answered by Masry_c777 2 · 0 0

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