Find the points on the given curve where the tangent line is horizontal or vertical
r=f(q)=cos(q)+sin(q)

Question

Find the points on the given curve where the tangent line is horizontal or vertical
r=f(q)=cos(q)+sin(q)

experimentx · Answer

http://www.wolframalpha.com/input/?i=polar+plot+r+%3D+sin+theta+%2B+cos+theta it's circle ... you can do this using rectangular coorinates

experimentx · Answer

If you want to do it in polar coordinates then, http://tutorial.math.lamar.edu/Classes/CalcII/PolarTangents.aspx

anonymous · Answer

got it Thanks dude

experimentx · Answer

it seems that equation of line in polar coordinate is 
$$ y = mx + c \implies r(\sin\theta - m\cos \theta) = c \implies r = \frac{c}{(\sin\theta - m\cos\theta)}$$

Find the values of m, using the above formula,

experimentx · Answer

I mean from the link i posted above, and equate it with 0 and $ \infty $ and find the value of $r$ and $ \theta $ and put them in above equation of line to find c, then you have your tangents.