#Proof by induction question, HELPPP

30 messages · Page 1 of 1 (latest)

solar ermine
wintry dagger
#

wth is prove by induction 💀

shell depot
solar ermine
#

ye

#

but dunno how to do this

shell depot
#

okay lemme just write it down see if it's any clearer

#

kind of hard to explain

solar ermine
#

tysm!!

shell depot
#

Then obviously just say, shown true for n=1, assumed true for n=k …

solar ermine
#

oh yeah

#

thank you so much honestly

solar ermine
#

@shell depot i cant do this one cant figure the algebra part

shell depot
solar ermine
#

okay ill try that

shell depot
#

$\sum_{r=1}^{n} 6r^3- 5r^2 + r$

shut groveBOT
shell depot
#

use summation formulas

#

so we get

#

$\frac{6n^2(n+1)^2}{4} - \frac{5(n)(n+1)(2n+1)}{6} + \frac{n(n+1)}{2}$

shut groveBOT
shell depot
#

you can take out a factor of n(n+1)/2 quite nicely

solar ermine
#

but is that induction

shell depot
solar ermine
#

ik but i have to prove by induction

shell depot
#

just same steps

#

show true for n=1

#

assume true for n=k

#

show it's true for n=k+1

#

when you do n=k+1 though your assumption for the series only holds to n = k