Study questions platform-wide or filter by specific tests with correct answers revealed.
Let $S=\left\{t\in\mathbb{R}: f(x)=|x-\pi|\cdot(e^{|x|}-1)\sin|x|\right.$ is not differentiable at $t\}$. Find $S$.
Check $x=0$: $f(x)=|x-\pi|(e^{|x|}-1)\sin|x|$. Near $x=0$, both $(e^{|x|}-1)$ and $\sin|x|$ have factors of $|x|$, so $f(x)\approx |x-\pi|\cdot|x|^2$ near 0, which is differentiable at 0.
Check $x=\pi$: near $\pi$, $(e^{|x|}-1)\sin|x|$ is smooth and non-zero ($e^\pi\sin\pi=0$!). Since $\sin\pi=0$, the product $(e^{|x|}-1)\sin|x|$ vanishes at $\pi$, making $f(x)=0$ near $\pi$ โ wait, $\sin\pi=0$, so $f(\pi)=0$. Checking differentiability more carefully shows $f$ is differentiable at $\pi$ too.
Therefore $S=\boldsymbol{\emptyset}$.
A car travels from X to Y with uniform speed $v_u$ and returns with uniform speed $v_d$. The average speed for the entire round trip is:
Let distance X to Y $= d$. Total distance $= 2d$.
Total time $= \dfrac{d}{v_u} + \dfrac{d}{v_d} = d\cdot\dfrac{v_u + v_d}{v_u v_d}$
Average speed $= \dfrac{2d}{d\cdot\dfrac{v_u+v_d}{v_u v_d}} = \mathbf{\dfrac{2v_u v_d}{v_u + v_d}}$ (harmonic mean)
Pender's Health Promotion Model (HPM, 1982; revised 1996) is grounded in social cognitive theory and emphasizes positive health behaviors rather than disease avoidance.
Key components of the HPM:
- Individual Characteristics and Experiences: Prior behavior, personal factors (biological, psychological, sociocultural)
- Behavior-Specific Cognitions and Affect: Perceived benefits, perceived barriers, perceived self-efficacy, activity-related affect, interpersonal and situational influences
- Behavioral Outcome: Commitment to a plan of action โ Health-promoting behavior
Sign in to join the conversation and share your thoughts.
Log In to Comment