Conversion from polar coordinates to regular form.

[rachelmaddie]

Hi. I need my work checked please.


Conversion from polar coordinates to regular form.
the transition formulas are:
x = r cos theta
y = r sin theta

sin theta = y/r
—> y = sin(2)r
y = sin(150 degrees)
y = (4, 5)

cos theta = x/r
—> x = cos(2)r
x = cos(150 degrees)
x = (-7, 79)

 

[HallsofIvy]

Hi. I need my work checked please.
View attachment 21084

Conversion from polar coordinates to regular form.
the transition formulas are:
x = r cos theta
y = r sin theta

sin theta = y/r
—> y = sin(2)r
y = sin(150 degrees)

times 9

y = (4, 5)

Since sin(150)= 1/2, 9 times sin(150)= 4.5
I know that some cultures use the "," but the space between the comma and 5 is strange.

cos theta = x/r
—> x = cos(2)r
x = cos(150 degrees)

times 9.
Since cos(150)= -sqrt(3)/2 which is about -0.8660, 9 times cos(150) is about -7.7942.

x = (-7, 79)

Again, I find this notation peculiar. I could understand -7.79 or -7,79 but the separation between "," and "7" together with the parenthese make this look like a point rather than a single number.

 

[jonah2.0]

Beer soaked comment follows.

Hi. I need my work checked please.
View attachment 21084

Conversion from polar coordinates to regular form.
the transition formulas are:
x = r cos theta
y = r sin theta

sin theta = y/r
—> y = sin(2)r
y = sin(150 degrees)
y = (4, 5)

cos theta = x/r
—> x = cos(2)r
x = cos(150 degrees)
x = (-7, 79)

Looks fine.
Why comma instead of period?

 

[rachelmaddie]

times 9


Since sin(150)= 1/2, 9 times sin(150)= 4.5
I know that some cultures use the "," but the space between the comma and 5 is strange.

times 9.
Since cos(150)= -sqrt(3)/2 which is about -0.8660, 9 times cos(150) is about -7.7942.


Again, I find this notation peculiar. I could understand -7.79 or -7,79 but the separation between "," and "7" together with the parenthese make this look like a point rather than a single number.

Is this better??

Conversion from polar coordinates to regular form.
the transition formulas are:
x = r cos theta
y = r sin theta

sin theta = y/r
—> y = sin(2)r
y = 9 times sin(150 degrees)
y = (4.5)

cos theta = x/r
—> x = cos(2)r
x = 9 times cos(150 degrees)
x = (-7. 79)

 

[HallsofIvy]

Yes- though the parentheses seem strange and unnecessary.