Posted by **mary** on Thursday, April 26, 2007 at 4:33pm.

for what value of r=4sinè have vertical tangent?

In polar coordinates? Theta=90 deg is vertical.

I do not know if you know how to differentiate polar coordinate equations so I changed your equation from polar to rectangular form, I don't know if that is the way you do it.

anyway I got x^2 + y^2 = 4y which is the equation of a circle.

I differentiated that

2x + 2y(dy/dt) = 4dy/dt

.

.

dy/dt = -x/(y-2)

for the tangent to be a vertical line, its slope must be undefined.

This happens when the denominator is 0

so y-2=0

y=2

then substitute that in the equation for x=2

so in Cartesian form the point is (2,2), making an angle of 45º or pi/4 radians.

in polar form (r,theta) it would be (√8,pi/4)

## Answer This Question

## Related Questions

- Pre-calculus; urgent ! Please help ! - 1.Graph the polar equation r=3-2sin(theta...
- Calculus please help ! - 1.Graph the polar equation r=3-2sin(theta) 2. Find the ...
- Math ! Please Help ! - 1.Graph the polar equation r=3-2sin(theta) 2. Find the ...
- precalculus - convert the equation y^2 = 2x -x^2 into polar form. convert the ...
- Pre-calculus- URGENT - Convert the rectangular coordinate (-8,i (square root of ...
- Polar Equations - Identify each polar equation by changing the equation to ...
- precaculus - Convert the rectangular coordinate (2,-2) to polar form and find ...
- Polar to Rectangular Form - The letters r and theta represent polar coordinates...
- Calculus - Convert the polar equation to rectangular coordinates: r = 2-cos ...
- Pre-calculus HELP PLASE ! - 1.Write the rectangular equation in polar form. (x...

More Related Questions