Thread: Finding the equation for the normal

Find the equation of the normal to y = cosec(2x) at the point where x = pi/4.

Differentiating cosec(2x) = -2cot(2x)cosec(2x)
At x = pi/4, dy/dx = -2cot(pi/2)cosec(pi/2)

I am unable to get a value for the dy/dx of the tangent since cot(pi/2) is undefined! How should I continue or did I make any mistakes?

Thank you very much!

The cotangent function is not undefined there. Look at it again.

Originally Posted by Tutu

Find the equation of the normal to y = cosec(2x) at the point where x = pi/4.

Differentiating cosec(2x) = -2cot(2x)cosec(2x)
At x = pi/4, dy/dx = -2cot(pi/2)cosec(pi/2)

I am unable to get a value for the dy/dx of the tangent since cot(pi/2) is undefined! How should I continue or did I make any mistakes?

Thank you very much!

Surely if is undefined, then the tangent line is vertical. So wouldn't the normal line have to be horizontal?

Hi thanks! But aren't co tangents undefined? I cannot find q value, it keeps coming back undefined..unless I type the whole cot and cosec in?