SOLUTION: Use implicit differentiation to find the equation of the tangent line at the given point arctan(x+y)=y^2+pi/4 (1,0)

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Question 1189574: Use implicit differentiation to find the equation of the tangent line at the given point
arctan(x+y)=y^2+pi/4 (1,0)

Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!

arctan%28x%2By%29=y%5E2%2Bpi%2F4  @ (1,0)

We need the formula:  d%2Fdxarctan%28u%29%22%22=%22%22%28du%2Fdx%29%2F%281%2Bu%5E2%29

Let u+=+x%2By, then du%2Fdx+=+1%2Bdy%2Fdx.  For the right side,
pi%2F4 is just a constant and its derivative is 0.

%281%2Bdy%2Fdx%29%2F%281%2B%28x%2By%29%5E2%29%22%22=%22%222y%2Aexpr%28dy%2Fdx%29

Now we substitute x=1 and y=0, then solve for dy%2Fdx

%281%2Bdy%2Fdx%29%2F%281%2B%281%2B0%29%5E2%29%22%22=%22%222%280%29%2Aexpr%28dy%2Fdx%29

%281%2Bdy%2Fdx%29%2F%281%2B%281%29%5E2%29%22%22=%22%220

%281%2Bdy%2Fdx%29%2F%281%2B1%29%22%22=%22%220

%281%2Bdy%2Fdx%29%2F%282%29%22%22=%22%220

1%2Bdy%2Fdx%22%22=%22%220

dy%2Fdx%22%22=%22%22-1     

That's the slope of the tangent line

Now find the equation of the tangent line which goes thru
(1,0), which has the slope m = -1

y-0%22%22=%22%22-1%28x-1%29

y%22%22=%22%22-x%2B1



Edwin