hi, just wanted some guidance on these problems. so is this right.. using that is the sum right? also how would I solve for, i'm guessing there is also a trick for this..
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Yes, multiply your result from the first one by 9.
If we let the original series be S and factor, we can get and solve for S. Factor out 9/10: But what I have underbraced is So what we get is Solve for S=90
Originally Posted by dankelly07 also how would I solve for, i'm guessing there is also a trick for this.. This is like Factor out x. This gives : You can see that is the derivative of , which is for . Thus Therefore
thanks alot, both answers help alot, just to make sure i've got it can you just double check I'm doing this right? factor out the x (derivative of ) so.. Close??
oops i think it was supposed to be 2/(1-x^3) wasn't it?
Originally Posted by dankelly07 thanks alot, both answers help alot, just to make sure i've got it can you just double check I'm doing this right? factor out the x (derivative of ) so.. Close?? if that is what you are trying to say that is wrong
You know from above that . The derivative is . Multiply by x, .
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