Question

help.

Answer 1

the last equation is supposed to be f'(1)=

Answer 2

@amistre64

Answer 3

after learning the derivative rules; you never go back to the limit definition ...

Answer 4

i knoow, but that's what he wants! ;/

Answer 5

then plug in the (1+h) into the function and algebra it out; its simple enough with that function

Answer 6

\[\lim\frac{5-2(1+h)-(5-2(1))}{(1+h)-1}\]

Answer 7

well
we have
\[f'(1)=\lim_{\Delta x \rightarrow 0}(f(1+\Delta x)-f(1))/\Delta x\]

we have f(1+delta x)= 5-(2*(1+delta x))
=3-2*(delta x)

& f(1)= 3

put these in above equation we have (3-2*(delta x)-3)/delta x

delta x gets cancelled & we have -2 as answer..

Answer 8

yeeah, thanks. i got it :))

Answer 9

good luck ;)