# positive second derivative

− Can you estimate the car's speed at different times? More than this, we want to understand how the bend in a function's graph is tied to behavior characterized by the first derivative of the function. Write several careful sentences that discuss (with appropriate units) the values of $$F(30)\text{,}$$ $$F'(30)\text{,}$$ and $$F''(30)\text{,}$$ and explain the overall behavior of the potato's temperature at this point in time. Interpretting a graph of $$f$$ based on the first and second derivatives, Interpreting, Estimating, and Using the Derivative, Derivatives of Other Trigonometric Functions, Derivatives of Functions Given Implicitly, Using Derivatives to Identify Extreme Values, Using Derivatives to Describe Families of Functions, Determining Distance Traveled from Velocity, Constructing Accurate Graphs of Antiderivatives, The Second Fundamental Theorem of Calculus, Other Options for Finding Algebraic Antiderivatives, Using Technology and Tables to Evaluate Integrals, Using Definite Integrals to Find Area and Length, Physics Applications: Work, Force, and Pressure, Alternating Series and Absolute Convergence, An Introduction to Differential Equations, Population Growth and the Logistic Equation. d For many combinations of boundary conditions explicit formulas for eigenvalues and eigenvectors of the second derivative can be obtained. , A differentiable function $$f$$ is increasing at a point or on an interval whenever its first derivative is positive, and decreasing whenever its first derivative is negative. 0 When does your graph in (b) have positive slope? In everyday language, describe the behavior of the car over the provided time interval. The function is therefore concave at that point, indicating it is a local For that function, the slopes of the tangent lines are negative throughout the pictured interval, but as we move from left to right, the slopes get more and more negative as they get steeper. Now draw a sequence of tangent lines on the first curve. At a point where $$f'(x)$$ is positive, the slope of the tangent line to $$f$$ is positive. We can also use the Second Derivative Test to determine maximum or minimum values. }\) Velocity is neither increasing nor decreasing (i.e. It is positive before, and positive after x=0. The car moves forward when $$s'(t)$$ is positive, moves backward when $$s'(t)$$ is negative, and is stopped when $$s'(t)=0\text{. Hence the slope of the curve is decreasing, and we say that the function is decreasing at a decreasing rate. ( d ( By 2027, it is forecasted to be just 12 years. ] Fundamentally, we are beginning to think about how a particular curve bends, with the natural comparison being made to lines, which don't bend at all. The car reaches its peak speed of about \(7000$$ ft/min just after the time $$t=1$$ minute (and again just after the points $$t=4\text{,}$$ $$t=7\text{,}$$ and $$t=10$$ minutes). Choose the graphs which have a positive second derivative for all x. Similar options hold for how a function can decrease. x How can you tell? }\), $$v$$ is increasing on the intervals $$(0,1.1)\text{,}$$ $$(3,4.1)\text{,}$$ $$(6,7.1)\text{,}$$ and $$(9,10.1)\text{. What are the units on \(s'\text{? on an interval where \(a(t)$$ is zero, $$v(t)$$ is constant. }\), Sketch a careful, accurate graph of $$y = s'(t)\text{.}$$. third derivative. For instance, the inverse function formula for the second derivative can be deduced from algebraic manipulations of the above formula, as well as the chain rule for the second derivative. 2 }\) If the function $$f$$ is increasing on $$(a,b)$$ then $$f'(x) \geq 0$$ for every $$x$$ in the interval $$(a, b)\text{. The second derivative of a function f can be used to determine the concavity of the graph of f.[3] A function whose second derivative is positive will be concave up (also referred to as convex), meaning that the tangent line will lie below the graph of the function. How does the derivative of a function tell us whether the function is increasing or decreasing at a point or on an interval? }$$ Moreover, because $$v(t) = s'(t)\text{,}$$ it follows that $$a(t) = v'(t) = [s'(t)]' = s''(t)\text{,}$$ so acceleration is the second derivative of position. u What physical property of the bungee jumper does the value of $$h''(5)$$ measure? }\) This is connected to the fact that $$g''$$ is negative, and that $$g'$$ is negative and decreasing on the same intervals. Note that a central difference just calculates the slope of a secant line between two input values whose midpoint is $$a\text{.}$$. ) The Second Derivative Test. [6][7] Note that the second symmetric derivative may exist even when the (usual) second derivative does not. We also provide data for $$F'(t)$$ in Table1.92 below on the right. As a result of the concavity test, the second derivative can also be used to reveal minimum and maximum points. Recall that a function is concave up when its second derivative is positive, which is when its first derivative is increasing. Examples of functions that are everywhere concave up are $$y = x^2$$ and $$y = e^x\text{;}$$ examples of functions that are everywhere concave down are $$y = -x^2$$ and $$y = -e^x\text{.}$$. While the car is speeding up, the graph of $$y=s'(t)$$ has a positive slope; while the car is slowing down, the graph of $$y=s'(t)$$ has a negative slope. Following this same idea, $$v'(t)$$ gives the change in velocity, more commonly called acceleration. ″ What are the units on $$s'\text{? The car's position function has units measured in thousands of feet. Since \(s''(t)$$ is the first derivative of $$s'(t)\text{,}$$ then whenever $$s'(t)$$ is increasing, $$s''(t)$$ must be positive. In Figure1.86 to consider, what does that tell you is what you get when you the! Only if its first derivative zero, \ ( y = v ( t ) \.... 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