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Mathematics 15 Online
OpenStudy (butterflydreamer):

MATHEMATICAL INDUCTION. Help please!! :) http://prntscr.com/5tukym

OpenStudy (anonymous):

ok show its true for first derivative , assume its true for n derivative then induction step to show its true for n+1 i'll skip first 2 step and will go to the third one

OpenStudy (butterflydreamer):

yepp okay!

OpenStudy (butterflydreamer):

Step 1 is usually to prove true for n= 1 right? Then assume n= k Then we're required to prove n= k+1 is also true.. i think?

OpenStudy (anonymous):

\(\begin{align*} \frac{d^{k+1}y}{dx^{k+1}} &= \left (\frac{d^{k}y}{dx^{k}} \right )' \\ &=\left (e^x(x+k) \right )' \\ &= (e^x)'(x+k)+e^x(x+k)'\\ &= e^x(x+k)+e^x \\ &= e^x(x+k+1) \end{align*}\)

OpenStudy (anonymous):

eh u can solve of term of n or k not a matter

OpenStudy (butterflydreamer):

hmm alright. I think i understand it..

OpenStudy (anonymous):

eh im here incase u dont

OpenStudy (butterflydreamer):

okay so i know the first step is generally to prove true for n=1 right? And we want to show that LHS = RHS But i'm not sure what's the LHS and what is the RHS that we're using???

ganeshie8 (ganeshie8):

you're inducting on \(n\) here for the base case, you need to show that the given statement is true for \(n=1\)

OpenStudy (anonymous):

ok first step y=xe^x u wanna show y'=e^x(x+1)

ganeshie8 (ganeshie8):

you need to show below is true \[\dfrac{d^1y}{dx^1} = e^x(x+1)\]

OpenStudy (butterflydreamer):

ahh okay. So LHS would be = d/dx (xe^x) = (1) e^x + e^x (x) THEN use the product rule so: = (1+ x) e^x and RHS would be (1+x) e^x ? So LHS= RHS therefore, true for n= 1 ?

ganeshie8 (ganeshie8):

Looks perfect to me!

OpenStudy (anonymous):

yosh

OpenStudy (anonymous):

yosh?

OpenStudy (anonymous):

eh wio it means yes

ganeshie8 (ganeshie8):

she says yosh for yes when eating icecream

OpenStudy (butterflydreamer):

Then after that i would.. substitute n=k into d^n (y) / dx^n = e^x (x +n) Assume n= k true i.e d^k y/ dx^k = e^x (x + k) Then prove n = k+1 is also true (WHICH @Marki proved) right?

OpenStudy (anonymous):

yep u got it

OpenStudy (butterflydreamer):

okey dokeys! Thanks guuuyyss! @Marki enjoy your ice cream?? @ganeshie8 thanks for helping as usual :)

OpenStudy (anonymous):

sure rofl

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