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Find the equation of the normal to the curve y= 5tan(x) -3  at the point where x= π/4.

 Jan 28, 2016

Best Answer 

 #1
avatar+33661 
+9

First get the tangent slope at x =  π/4

 

Slope = dy/dx = 5(tan(x)^2 + 1)    tan( π/4) = 1, so slope at x =  π/4 is 5*2 = 10

 

The slope of the normal is -1/the tangent slope, namely -1/10

 

The equation of the normal is therefore y = -x/10 + c where c is a constant, found from the fact that the line goes through the point ( π/4, 5tan( π/4)-3)  or ( π/4, 2)

 

2 = - π/40 + c so c = 2+ π/40  

 

equation of normal:  y = -x/10 + 2+ π/40

 Jan 28, 2016
 #1
avatar+33661 
+9
Best Answer

First get the tangent slope at x =  π/4

 

Slope = dy/dx = 5(tan(x)^2 + 1)    tan( π/4) = 1, so slope at x =  π/4 is 5*2 = 10

 

The slope of the normal is -1/the tangent slope, namely -1/10

 

The equation of the normal is therefore y = -x/10 + c where c is a constant, found from the fact that the line goes through the point ( π/4, 5tan( π/4)-3)  or ( π/4, 2)

 

2 = - π/40 + c so c = 2+ π/40  

 

equation of normal:  y = -x/10 + 2+ π/40

Alan Jan 28, 2016

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