Calculus1
7 Online
OpenStudy (anonymous):
Find equations of the tangent line and normal line to the curve at the given point.
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OpenStudy (anonymous):
\[y=\frac{ \sqrt{x} }{ x+9 }\]
OpenStudy (anonymous):
Given point (1,0.1)
OpenStudy (welshfella):
first you nee to find the derivative y' . This will give you the slope of the line in terms of x.
OpenStudy (anonymous):
\[\frac{(x+9)(\frac{ 1 }{ 2 } x ^{-1/2})-(x ^{1/2})(1)}{ (x+9)^2}\]
OpenStudy (welshfella):
yes thats correct
now plug in x = 1 to find the numerical value of slope at the point (1,0.1)
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OpenStudy (welshfella):
1/2 * (1)^(-1/2) = 1/2 * 1 /1^ 1/2
OpenStudy (welshfella):
= 1/2
OpenStudy (anonymous):
is the slope 4/100?
OpenStudy (welshfella):
right or 0.04
OpenStudy (anonymous):
y-0.1=.04(x-1)
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OpenStudy (anonymous):
y=.04x-.04+0.1
OpenStudy (welshfella):
yes thats the tangent
OpenStudy (anonymous):
y=.04x+.06
OpenStudy (welshfella):
no - i think you have the last number wrong
OpenStudy (anonymous):
ohh
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OpenStudy (welshfella):
sorry you are right!! my bad arithmetic!
OpenStudy (anonymous):
ok xD
OpenStudy (welshfella):
Now the normal as a slope of -1 / 0.04
OpenStudy (anonymous):
is the normal line perpendicular?
OpenStudy (welshfella):
yes
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OpenStudy (anonymous):
y-.1=-25(x-1)
OpenStudy (anonymous):
y=-25x+25+.1
OpenStudy (anonymous):
y=-25x+25.1
OpenStudy (welshfella):
right
OpenStudy (anonymous):
Thank you so much! You were so helpful :)
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OpenStudy (welshfella):
yw
OpenStudy (welshfella):
you did pretty well too!!
OpenStudy (anonymous):
aw thanks :)