We read your photo as:

Find the stationary points of the function y = 2x3 + 5 and determine their nature.

Mathematics

ScanSolve AI Answer

Answer

(0, 5) which is a point of inflection\text{(0, 5) which is a point of inflection}

Graph of y = 2x³ + 5

Use the left and right arrow keys to trace the curve, up and down to jump between key points, and plus and minus to zoom.

Key points of y = 2x³ + 5
Pointxy
x-intercept−1.360
y-intercept05

Step-by-step solution

5 steps
  1. Find the first derivative of the function.

    Given the function y=2x3+5y = 2x^3 + 5.
    Differentiate yy with respect to xx:

    dydx=ddx(2x3+5)=6x2\frac{dy}{dx} = \frac{d}{dx}(2x^3 + 5) = 6x^2
  2. Find the x-coordinates of the stationary points by setting the first derivative to zero.

    6x2=06x^2 = 0 x2=0x^2 = 0 x=0x = 0

    There is one stationary point at x=0x=0.

  3. Find the y-coordinate of the stationary point by substituting x=0x=0 into the original equation.

    y=2(0)3+5=0+5=5y = 2(0)^3 + 5 = 0 + 5 = 5

    The stationary point is (0,5)(0, 5).

  4. Find the second derivative to determine the nature of the stationary point.

    Differentiate dydx=6x2\frac{dy}{dx} = 6x^2 with respect to xx:

    d2ydx2=ddx(6x2)=12x\frac{d^2y}{dx^2} = \frac{d}{dx}(6x^2) = 12x
  5. Evaluate the second derivative at the stationary point x=0x=0.

    d2ydx2∣x=0=12(0)=0\frac{d^2y}{dx^2} \Big|_{x=0} = 12(0) = 0

    Since the second derivative is 0, we need to check the sign of the first derivative around x=0x=0 to confirm the nature of the point.
    For x<0x < 0 (e.g., x=−1x = -1), dydx=6(−1)2=6>0\frac{dy}{dx} = 6(-1)^2 = 6 > 0.
    For x>0x > 0 (e.g., x=1x = 1), dydx=6(1)2=6>0\frac{dy}{dx} = 6(1)^2 = 6 > 0.
    Since the sign of dydx\frac{dy}{dx} does not change around x=0x=0 (it remains positive), the point (0,5)(0, 5) is a point of inflection.

    The stationary point is (0, 5) which is a point of inflection\text{(0, 5) which is a point of inflection}.

Was this helpful?

Try one yourself

A new problem that tests the same skill.

Still stuck on this one?

Ask a follow-up, and the answer starts from this question.

Got a different question?Ask your own question
Handwritten step-by-step solution preview

Handwritten Step-by-Step Solution

Get this as a handwritten image on WhatsApp — like a tutor wrote it for you.

Try on WhatsApp