Finding the Equation of a Tangent

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In summary, the conversation was about finding the equation of the tangent at a given point for the function y=3cscx. The solution involved finding the slope by differentiating the function and simplifying it using trigonometric identities. The final answer was found to be y=(3\sqrt{2}/2)x + b.
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Homework Statement


Find the equation of the tangent at the point indicated
y=3cscx
x=pi/4

2. The attempt at a solution

So to do the question you need a point (which I am given), the slope and then you need to substitute that all into y=mx+b.

I believe I have differentiated correctly with

y=3(-cot(x)csc(x))

Then I find the slope by inserting pi/4 into the differentiated equation

y=3(-cot(pi/4)csc(pi/4))

After this is done I put everything into y=mx+b, and this is where my problem is. Is there anyways to simplify 3csc(pi/4) and 3(-cot(pi/4)csc(pi/4))? I think I remember doing something similar in math a long time ago but I forgot now. The final answer does not include -cot or csc so there must be a way I don't remember.
 
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What is cosec and cotangent in terms of the other trig functions?

1/(sin x) = csc x
1/( tan x) = cot x

So 3 csc (pi/4) = [itex]\frac{3}{\sin (\pi/4)}[/itex].

The exact value for sin (pi/4) is 1/(sqrt2) so..
[itex]3 \csc (\pi/4) = \frac{3}{\sqrt{2}} = \frac{3\sqrt{2}}{2}[/itex]

So the same for cot, knowing tan (pi/4) = 1.
 

FAQ: Finding the Equation of a Tangent

What is the equation of a tangent?

The equation of a tangent is a mathematical expression that represents a straight line that touches a curve at a single point. It is used to find the slope or rate of change at that point on the curve.

How do you find the equation of a tangent?

To find the equation of a tangent, you first need to find the slope of the curve at the point of tangency. This can be done by taking the derivative of the curve at that point. Then, you can use the slope-intercept form of a line, y = mx + b, where m is the slope and b is the y-intercept, to write the equation of the tangent line.

What is the importance of finding the equation of a tangent?

Finding the equation of a tangent is important because it allows us to determine the slope, or rate of change, of a curve at a specific point. This can be useful in many applications, such as calculating the velocity of an object or determining the maximum or minimum value of a function.

Can the equation of a tangent be used to find the equation of a normal?

Yes, the equation of a tangent can be used to find the equation of a normal, which is a line that is perpendicular to the tangent at the point of tangency. To find the equation of a normal, you would first find the slope of the tangent line and then take the negative reciprocal of that slope to find the slope of the normal line. You can then use the point-slope form of a line, y - y1 = m(x - x1), to write the equation of the normal line.

Are there any special cases when finding the equation of a tangent?

Yes, there are some special cases when finding the equation of a tangent. For example, if the curve is a straight line, then the equation of the tangent will be the same as the equation of the curve. Additionally, if the curve has a vertical tangent, then the slope will be undefined and the equation of the tangent will be in the form x = a, where a is the x-coordinate of the point of tangency.

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