Gradient Differentiation 674462
1. **Problem (a):** Find the gradient of the curve $y = 3x^4 - 2x^2 + 5x - 2$ at points $(0, -2)$ and $(1, 4)$.
The gradient of a curve at a point is given by the derivative $\frac{dy}{dx}$ evaluated at that point.
First, differentiate:
$$\frac{dy}{dx} = \frac{d}{dx}(3x^4) - \frac{d}{dx}(2x^2) + \frac{d}{dx}(5x) - \frac{d}{dx}(2) = 12x^3 - 4x + 5$$
Evaluate at $x=0$:
$$12(0)^3 - 4(0) + 5 = 5$$
Evaluate at $x=1$:
$$12(1)^3 - 4(1) + 5 = 12 - 4 + 5 = 13$$
So, gradients are 5 at $(0,-2)$ and 13 at $(1,4)$.
2. **Problem (b):** Find coordinates on $y = 3x^2 - 7x + 2$ where gradient is $-1$.
Differentiate:
$$\frac{dy}{dx} = 6x - 7$$
Set gradient equal to $-1$:
$$6x - 7 = -1$$
$$6x = 6$$
$$x = 1$$
Find $y$ at $x=1$:
$$y = 3(1)^2 - 7(1) + 2 = 3 - 7 + 2 = -2$$
Coordinates are $(1, -2)$.
3. **Problem (c):** Find differential coefficient of $y = 3x^2 \sin 2x$.
Use product rule: If $y = u v$, then $\frac{dy}{dx} = u'v + uv'$.
Let $u = 3x^2$, $v = \sin 2x$.
Calculate derivatives:
$$u' = 6x$$
$$v' = 2 \cos 2x$$
Apply product rule:
$$\frac{dy}{dx} = 6x \sin 2x + 3x^2 (2 \cos 2x) = 6x \sin 2x + 6x^2 \cos 2x$$
**Final answers:**
(a) Gradient at $(0,-2)$ is $5$, at $(1,4)$ is $13$.
(b) Coordinates where gradient is $-1$ are $(1, -2)$.
(c) Differential coefficient is $$\frac{dy}{dx} = 6x \sin 2x + 6x^2 \cos 2x$$.