Question

Please help with Number 10
I am very confused

Answer 1

Step-by-step explanation:

We have,

$y = 4 {x}^{3} - 4 {x}^{2} - 10x + 12$

Differentiating both sides w.r.t x ,

$\frac{dy}{dx} = 12 {x}^{2} - 12x - 10$

$\implies( \frac{dy}{dx})_{x = 1} = 12 - 12 - 10 = - 10$

At x = 1, the value of y = 2

Now, the equation of tangent is

$(y - 2) = - 10(x - 1)$

$\implies \: y - 2 = - 10x + 10$

$\implies10x + y = 12$

x - coordinate of point B is - 1

Putting this in equation of tangent, we get,

y = 22