a differential equation is an equation involving an unknown function and its derivatives. consider the…

a differential equation is an equation involving an unknown function and its derivatives. consider the differential equation y(t)+y(t)=0.\na. show that y = a sin t satisfies the equation for any constant a.\nb. show that y = b cos t satisfies the equation for any constant b.\nc. show that y = a sin t + b cos t satisfies the equation for any constants a and b.\na. find y(t) for y = a sin t. choose the correct answer below.\na. y(t)=a cos t\nb. y(t)= - a cos t\nc. y(t)=a sin t\nd. y(t)= - a sin t\ndoes this show that y(t)+y(t)=0 for y = a sin t?\nno\nyes
Answer
Explanation:
Step1: Find first - derivative of $y = A\sin t$
Using the derivative formula $\frac{d}{dt}(\sin t)=\cos t$, we have $y'(t)=A\cos t$.
Step2: Find second - derivative of $y = A\sin t$
Differentiate $y'(t)=A\cos t$ with respect to $t$. Since $\frac{d}{dt}(\cos t)=-\sin t$, we get $y''(t)=-A\sin t$.
Step3: Substitute $y$ and $y''$ into the differential equation
Substitute $y = A\sin t$ and $y''(t)=-A\sin t$ into $y''(t)+y(t)$. We have $y''(t)+y(t)=-A\sin t + A\sin t=0$.
For part b:
Step1: Find first - derivative of $y = B\cos t$
Using the derivative formula $\frac{d}{dt}(\cos t)=-\sin t$, we get $y'(t)=-B\sin t$.
Step2: Find second - derivative of $y = B\cos t$
Differentiate $y'(t)=-B\sin t$ with respect to $t$. Since $\frac{d}{dt}(\sin t)=\cos t$, we have $y''(t)=-B\cos t$.
Step3: Substitute $y$ and $y''$ into the differential equation
Substitute $y = B\cos t$ and $y''(t)=-B\cos t$ into $y''(t)+y(t)$. We get $y''(t)+y(t)=-B\cos t + B\cos t = 0$.
For part c:
Step1: Find first - derivative of $y=A\sin t + B\cos t$
Using the sum - rule of differentiation and the derivative formulas $\frac{d}{dt}(\sin t)=\cos t$ and $\frac{d}{dt}(\cos t)=-\sin t$, we have $y'(t)=A\cos t - B\sin t$.
Step2: Find second - derivative of $y=A\sin t + B\cos t$
Differentiate $y'(t)=A\cos t - B\sin t$ with respect to $t$. We get $y''(t)=-A\sin t - B\cos t$.
Step3: Substitute $y$ and $y''$ into the differential equation
Substitute $y = A\sin t + B\cos t$ and $y''(t)=-A\sin t - B\cos t$ into $y''(t)+y(t)$. We have $y''(t)+y(t)=(-A\sin t - B\cos t)+(A\sin t + B\cos t)=0$.
Answer:
a. The correct answer for $y''(t)$ when $y = A\sin t$ is D. $y''(t)=-A\sin t$, and $y''(t)+y(t)=0$ for $y = A\sin t$ (Yes). b. For $y = B\cos t$, $y'(t)=-B\sin t$, $y''(t)=-B\cos t$, and $y''(t)+y(t)=0$. c. For $y = A\sin t + B\cos t$, $y'(t)=A\cos t - B\sin t$, $y''(t)=-A\sin t - B\cos t$, and $y''(t)+y(t)=0$.