Calculating the Tangent to a Parametric Curve at a Given Point

53Mark53
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Homework Statement



Consider the parametric curve given by:

x=6cos(2t),

y=t5/2.

Calculate the equation of the tangent to this curve at the point given by t=π/4, in the form y=mx+c.

The tangent is given by y=

Homework Equations


The Attempt at a Solution


[/B]
the answer that I got was y=-0.145x+0.547 but it says that it is wrong

I did this by subbing in the value of t for x and y and also the differential of x and y and then calculating the slope

but I am not sure what I have done wrong
 
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53Mark53 said:

Homework Statement



Consider the parametric curve given by:

x=6cos(2t),

y=t5/2.

Calculate the equation of the tangent to this curve at the point given by t=π/4, in the form y=mx+c.

The tangent is given by y=

Homework Equations


The Attempt at a Solution


[/B]
the answer that I got was y=-0.145x+0.547 but it says that it is wrong

I did this by subbing in the value of t for x and y and also the differential of x and y and then calculating the slope

but I am not sure what I have done wrong

How can we know what you did wrong if you do not show your work?
 
53Mark53 said:

Homework Statement



Consider the parametric curve given by:

x=6cos(2t),

y=t5/2.

Calculate the equation of the tangent to this curve at the point given by t=π/4, in the form y=mx+c.

The tangent is given by y=

Homework Equations


The Attempt at a Solution


[/B]
the answer that I got was y=-0.145x+0.547 but it says that it is wrong

I did this by subbing in the value of t for x and y and also the differential of x and y and then calculating the slope

but I am not sure what I have done wrong

Do you mean ##y = (5/2)t##, ##y = t^{5/2}##, ##y = t^5/2 = \frac{1}{2} t^5##, or what? Use parenthesis, like this: y = (5/2)t or y = t*(5/2) or y = t^(5/2) or y =(t^5)/2, or whatever is appropriate.
 
Ray Vickson said:
Do you mean ##y = (5/2)t##, ##y = t^{5/2}##, ##y = t^5/2 = \frac{1}{2} t^5##, or what? Use parenthesis, like this: y = (5/2)t or y = t*(5/2) or y = t^(5/2) or y =(t^5)/2, or whatever is appropriate.

sorry the question didnt copy properly it should say t^(5/2)
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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