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Maths
A Level

A curve has the equation, 6x^2 +3xy−y^2 +6=0 and passes through the point A (-5, 10). Find the equation of the normal to the curve at A.

Use implicit differentiation on original equation-
12x + 3x(dy/dx) + 3y - 2y(dy/dx) = 0
dy/dx= -12x -3y/(3x-2y) at A, x= -5 and y= 10 therefore, dy/dx=-6/7

To find the normal of t...

Answered by Chantal G. Maths tutor
5493 Views

A curve has the equation y = (x^2 - 5)e^(x^2). Find the x-coordinates of the stationary points of the curve.

This requires the chain rule and the product rule to be used to differentiate the function. The substitution u = x2 can be used to make this easier. Using this, du/dx = 2x and y = (u-5)eu<...

Answered by Oliver J. Maths tutor
3293 Views

Find a local minimum of the function f(x) = x^3 - 2x.

To find a local minimum (i.e. a point where the function changes from a negative slope into a positive slope), we first need to find all points where the slope of the function is zero. The first derivativ...

Answered by Karoline H. Maths tutor
3192 Views

The equation " x^3-3x+1=0 " has three real roots. Show that one of the roots lies between −2 and −1

A simple way to prove this is to sub in the values that we are given. so f(x) will represent our equation x^3-3x+1 (that is f(x) = x^3-3x+1)f(-2) = -1 < 0f(-1) = 3 > 0The first thing we notice is th...

Answered by James B. Maths tutor
7228 Views

Solve x^2 + x=12 by factorising

Start off with:x2+x=12Subtract 12 from both sides:x2+x-12=0Factorise:(x-3)(x+4)=0Solution is therefore:x=3 or x=-4

Answered by Duwan B. Maths tutor
2622 Views

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