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**help with some trigonometry problems please!!**

hello everybody! how's everyone doing? i hope you guys are well and your homework is going great!

i posted another help thread but it was in the wrong section! sorry! but i got great help there!

ok here's my new problem. i tried, but i just don't know how i could do it! it's a bit long but please bear with me.

**Write each rectangular equation in polar form.**

**26.**y=-5

**27.**x=10

**28.**x^2+y^2=7 (latex version: [tex] x^{2}+y^2=7[/tex])

**29.**2x^2+2y^2=5y (latex version:[tex]2x^{2}+2y^{2}=5y[/tex])

This is what i did:

**26:**y=-5 ===> I used the pythagorean theorem: r=√(x^2+y^2)

r=√(x^2+(-5)^2) ---> I plugged in the value for y into this formula

r=√(x^2+25) ---> -5 squared is 25

r=5+√(x^2) ---> 25 square rooted is 5

r=5+x ---> the square root of x squared is x...isn't it?[?]

and also, i said that θ=Undefined because they did not give me an "x" value, so i just said that x=0; because, the formula

for converting a rectangular coordinate to polar coordinate is:

[tex]\theta=tan^{-1}(y/x)[/tex], when x>0

and x cannot be zero in the denominator spot right?

and that's what my answer is. but i have this feeling that it is not right! because i did the next problem which is very similar

to this one. (and sadly the answers are not in the back of the book for even number problems)

**27:**basically i did the same exact thing as number 26, and got this:

r=10+y --->again, here, θ=zero because of the same reason up there (except this time i didn't have a "y" value, so i said

y=0 and got zero because arctan 0=0).

so i checked in the back to see if this one was right, but it wasn't.[b(] [b(] this is what was there (the answer for #27)

r=10secθ

HELP!!

then, i got to number 28, and i didn't have a clue as to how to even begin this problem! same with 29! can someone please

help me with these? any help is appreciated! thanks a lot in advance!

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