Limit question is attached as a pic
anotehr question please help with
which one?
please help with both
@myininay which one are you doing?
\[f(x)=6x^2-2x\] \[f(c)=6c^2-2c \] \[f(c+h)=6(c+h)^2-2(c+h)=6(c^2+2ch+h^2)-2c-2h \] \[f(c+h)=6c^2+12ch+6h^2-2c-2h \] \[f'(c)=\lim_{h \rightarrow 0}\frac{f(c+h)-f(c)}{h}=\lim_{h \rightarrow 0} \frac{(6c^2+12ch+6h^2-2c-2h)-(6c^2-2c)}{h}\] \[f'(c)=\lim_{h \rightarrow 0} \frac{12ch+6h^2-2h}{h}\] \[f'(c)=\lim_{h \rightarrow 0}(12c+6h-2)=12c+6(0)-2=12c-2\]
wow!
now if you want f'(3) replace c with 3
so is it 48
@sabrina, impressive huh? what is more impressive is that in a week you will be able to do this problem in your head using a quick and easy shortcut
but definitions are awesome
cool wat is teh shortcut
what is the slope of y=constant
0
The answer is 34.
0 we say y'=0 if y=constant if \[y=6x^2 \text{ we say} y'=6(2)x^{2-1}=12x^{1}=12x\] we can use the definition to prove the general case \[y=x^n => y'=nx^{n-1}\]
we can this the power rule
for second one you will find that the slope of the tangent line is -27, which means the slope of the "normal" line (perpendicular line) will be \[\frac{1}{27}\] since there is only one choice of lines with that slope, that is your answer
*call?
yep 36-2=34 not 48
oh sorry... and @ satelite that is answer chice 3 right
yeah i guess. i didn't actually finish the problem. i just saw that there was only one line with slope \[\frac{1}{27}\] and chose that one
wow that took no computation at all!! i wish i cud think that fast to save me time in tests
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