simple slope question that I can't make sense of

• Sep 21st 2012, 03:04 PM
kingsolomonsgrave
simple slope question that I can't make sense of
does one go about finding the slope of y=20-4*sqrt(x) when x=4 and y=11

From what I can tell y should = 12 when x =4

that aside, when I do the rate of change algebra f(x+h)-f(x)/h

I get

[-4(sqrt(x+h)-sqrt(x))]/h

am I on the wrong track?
• Sep 21st 2012, 03:46 PM
Plato
Re: simple slope question that I can't make sense of
Quote:

Originally Posted by kingsolomonsgrave
does one go about finding the slope of y=20-4*sqrt(x) when x=4 and y=11
From what I can tell y should = 12 when x =4
that aside, when I do the rate of change algebra f(x+h)-f(x)/h
I get
[-4(sqrt(x+h)-sqrt(x))]/h

$\frac{{4\sqrt x - 4\sqrt {x + h} }}{h} = \frac{{4\sqrt x - 4\sqrt {x + h} }}{h}\left( {\frac{{4\sqrt x + 4\sqrt {x + h} }}{{4\sqrt x + 4\sqrt {x + h} }}} \right) = \frac{{ - 16}}{{4\sqrt x + 4\sqrt {x + h} }}$