stopandthink Posted October 11, 2012 Share Posted October 11, 2012 (edited) [math]\frac{(1+h)^2 - 1}{h} = \frac{1 + 2h + h^2 - 1}{h} = \frac{2h + h^2}{h} = \frac{h(2 + h)}{h} = 2 + h[/math] I'm currently using one of the forums tutorial on calculus... And i'm stuck with a problem. The problem is i know it works out because iv'e substituted "h" with an actual integer, and my dilemma is i can't figure out how it went from, [math]\frac{(1+h)^2 - 1}{h} = \frac{1 + 2h + h^2 - 1}{h}[/math] Ignore the /font font=monospace thing, can't figure out how to remove it Edited October 11, 2012 by stopandthink Link to comment Share on other sites More sharing options...
ewmon Posted October 11, 2012 Share Posted October 11, 2012 What happened to make the brackets go away? Link to comment Share on other sites More sharing options...
stopandthink Posted October 11, 2012 Author Share Posted October 11, 2012 I can't figure out how (1+h)^2 -1 = 1 + 2h+ h^2-1 my answer is 2+ 2h^2-1 Of course, my answer is incorrect but i cant see where it is i'm making a mistake. Link to comment Share on other sites More sharing options...
Axioms Posted October 11, 2012 Share Posted October 11, 2012 Look at how you are expanding your brackets of (1+h)^2. It is the same as saying (1+h)(1+h)... From here you should get (1+ 2h + h^2) I dont know where you are making your mistake so if you could show what you did then that could be helpful. I am pretty certain though that you are not expanding your brackets and multiplying out correctly. Remember from (1 + h)(1 + h) you must multiply every term in the first bracket by every term in the second bracket: i.e. (1*1 + 1*h + h*1 + h*h). I think this was called FOIL.. First outter inner last or something like that. If you are still struggling look up bracket expansion and how to multiply out of brackets. (x+1)^3 = (x+1)(x+1)(x+1) = (x+1)(x^2+2x+1)= ((x^3)+(2x^2)+(x) + (x^2)+)(2x)+(1)) try expand this: (x+5)^2 Link to comment Share on other sites More sharing options...
stopandthink Posted October 11, 2012 Author Share Posted October 11, 2012 Lol! i see what i did wrong, Ignore this post! Thanks. Look at how you are expanding your brackets of (1+h)^2. It is the same as saying (1+h)(1+h)... From here you should get (1+ 2h + h^2) I dont know where you are making your mistake so if you could show what you did then that could be helpful. I am pretty certain though that you are not expanding your brackets and multiplying out correctly. Remember from (1 + h)(1 + h) you must multiply every term in the first bracket by every term in the second bracket: i.e. (1*1 + 1*h + h*1 + h*h). I think this was called FOIL.. First outter inner last or something like that. If you are still struggling look up bracket expansion and how to multiply out of brackets. (x+1)^3 = (x+1)(x+1)(x+1) = (x+1)(x^2+2x+1)= ((x^3)+(2x^2)+(x) + (x^2)+)(2x)+(1)) try expand this: (x+5)^2 Thank you! i was stuck trying to work it out some other way... Lesson learned. Link to comment Share on other sites More sharing options...
Axioms Posted October 11, 2012 Share Posted October 11, 2012 No problem Link to comment Share on other sites More sharing options...
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