CALCULUS: FINDING THE ZERO OF A POLYNOMIAL help please :) drawing a picture "to illustrate what is happening" ... (see below)

Question

CALCULUS: FINDING THE ZERO OF A POLYNOMIAL  help please :) drawing a picture "to illustrate what is happening" ... (see below)

anonymous · Answer

attachment

anonymous · Answer

i have found the equation of the tangent... and the x intercepts but I don't think i've illustrated it properly..

anonymous · Answer

equation of tangent: $$y=f'(a)x+f(a)-af'(a)$$$$y=f'(a)(x-a)+f(a)$$
x intercept when y=0...$$x=\frac{ af'(a)-f(a) }{ f'(a) }$$

ganeshie8 · Answer

looks good

anonymous · Answer

|dw:1398073790359:dw|

ganeshie8 · Answer

ur teacher gave any feedback.. that its not sufficient explanation/illustration ?

anonymous · Answer

are you asking if my teacher gave me any feed back?  No - i'm on holidays atm... i was just wondering if this is all it is asking to do?

ganeshie8 · Answer

Yes, thats all it is asking, and ur work is looking very good.
if you want you may explain it using more words... eventhough the question is not asking u to give any written explanation on steps...

anonymous · Answer

ok great :) thanks for your help @ganeshie8

ganeshie8 · Answer

np :)

ganeshie8 · Answer

$\large   x=\frac{ af'(a)-f(a) }{ f'(a) } $


u may add a caveat saying $f'(a) \ne 0$ for x-intercept, and how the tangent looks like when $f'(a) =  0$ and talk about what happens to the x-intercept

ganeshie8 · Answer

@BarbaraKara   More work for you^^