/sci/ - Science & Math

>22
>mechanical engineering
>movies, short stories+novels, dancing, eating and preparing food
>N/A
>~6-9 excluding online
>~6-9 excluding online
>I'm not interested in STEM.
>>11603075
>recently uncloseted
<3 <3 <3
>>11607139
Am I normal?

>>/wsr/809597
>>/wsr/809620
>2
Draw a free body diagram and make sure to pick proper coordinates. Recall Hooke's law for springs. You should get the equation of motion for the mass: [math] F(t)-kx=m\ddot{x}\implies 4\ddot{x}+9x=\sin(3t/2) [/math]. Write down the characteristic equation and use the method of undetermined coefficients to get [eqn] x(t)=C_1\cos(3t/2)+C_2\sin(3t/2)-(1/12)t\cos(3t/2) [/eqn] Solve for the constants with initial conditions, C1=0, C2=1/18.
>3
It's just a separable ODE. Write down [eqn] \int2\text{ d}x=\int\frac{3\text{ d}y}{(1+y)(1-2y)}=\int\frac{1}{1+y}+\frac{2}{1-2y}\text{ d}y [/eqn] and compute.
>4
Part i is very easy. Part ii involves an integration factor. Recall that for [math] u'+f(x)u=g(x) [/math] you can let [math] \mu=\exp\int f(x)\text{ d}x [/math] then [math] u=\int\mu g(x)\text{ d}x/\mu [/math] and you finally end up with [math] u=2x+Cx^2 [/math]. You can easily get y now.

>>11558354
Remifag isn't banned for avatar shit.
>>11557313
Use the name they used at the time and gender neutral pronouns.
>>11558654
I realize I got good and shit mixed up. Feel free to fix.
>>11558493
Goldstein
>>11558980
>highschool
http://hyperphysics.phy-astr.gsu.edu/hbase/index.html
>>11558747
There's a harmonic function which agrees with your function on the border. Since harmonic functions satisfy medium value, the difference of your original function and the harmonic one does too. Mess around with Weierstrass's theorems on extrema

thank you based anon for the sophisticated OC

~UNANSWERED~

Physics
>>11403909
>>11405676

Math
>>11405061
>>11405068
>>11407710
>>11407916 (answered, I think)
>>11409497
>>11410597
>>11414205
>>11414831

Biology
>>11411726
>>11414393

Chemistry
>>11404206 (I believe this was answered in his thread)
>>11411363

Engineering
>>11403612

/g/
>>11404421
>>11404620

Stupid
>>11403705
>>11403745 (smartest = stupid = miscellaneous)
>>11404064
>>11406922 (don't wash your panties on hot, air dry them)
>>11410000
>>11410954
>>11412194
>>11413582
>>11413766
>>11414791
>>11414802 (desmos)