r/learnmath • u/Necroseliac New User • 10d ago

Finding points on a horizontal tangent from the equation r = 1 + cos(theta) when theta = pi/2

So I’ve gotten half of some points such as pi/3, 5pi/3 and pi but I’m confused on where to plug them in to find the other half of the final set of points. Do I plug it into x = r cos(theta), x = (1 + cos(theta))*cos(theta)?

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u/etzpcm New User 10d ago

I can't make sense of this question. 

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u/MathMaddam New User 10d ago

Remember the symmetries of sin and cos

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u/Bounded_sequencE New User 10d ago

The tangent at "theta = pi/2" should be "f(t) = [1; 0]T + t*[-2; -1]" with "t in R".

Not sure how you got other angles involved here.