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By Satchamp (Satchamp) on Thursday, June 03, 2004 - 09:49 pm: Edit |

1. Which of the following values is defined?

(A) arcsin 2

(B) tan 90

(C) sec 90

(D) arctan 0

(E) cot 270

2. S and T are the centers of their respective circles. The two circles are mutually tangent at point U. If segment RS = d, what is the radius of the smaller circle in terms of d and ?

(A) d cos A

(B) d sin A

(C) d(cosA – sinA)

(D) d(sinA – cosA)

(E) d(sinA + cosA)

hey...the 1st one is D and the second one is C

cud u plz explain Why???

By Baseballnbooks (Baseballnbooks) on Thursday, June 03, 2004 - 10:07 pm: Edit |

1. (d)

I dont know 2

By Qwert271 (Qwert271) on Thursday, June 03, 2004 - 10:12 pm: Edit |

1. the tangent of 0 degrees equals 0, therefore there is an angle that when put into the tan formula, you will get 0. B, C, and E are infinite, and A is just plain impossible.

2. You may not have given us all the info that you have because you're introducing variables and letters that you never defined.

By Satchamp (Satchamp) on Thursday, June 03, 2004 - 10:43 pm: Edit |

oooh......there was a diagram..never mind that

but isnt cot270 =0 ??

SO THAT WOULD BE DEFINEd right?

By Qwert271 (Qwert271) on Thursday, June 03, 2004 - 10:46 pm: Edit |

I think you're right. I just skipped over it without reading. My bad. Maybe it's a typo, either way I wouldn't worry about it.

By Satchamp (Satchamp) on Thursday, June 03, 2004 - 10:56 pm: Edit |

also technically,

doesnt arctan0 have infinite values....

coz only Arctan0=0

while arctan0= 0, 180, 360 and so on.

its an example online at the sparknotes website.....i got the link

http://www.sparknotes.com/testprep/books/sat2/math2c/chapter9section12.rhtml

yeah.....check it out

By R2005 (R2005) on Friday, June 04, 2004 - 01:03 am: Edit |

Satchamp...

sparknotes says the answer is d.

BUT, cot=1/tan OR cos/sin

sin 1.5pi=1

cos 1.5pi=0

so, tan (sin/cos)1.5pi = impossible

BUT, cot (cos/sin)1.5pi= 0/1= 0=defined

but d, after plugging into my calculator, is defined as well.

BUT, when i type in 1/tan(1.5pi) in it, it's ERROR..

WTF?

help help help

By Aim78 (Aim78) on Friday, June 04, 2004 - 01:09 am: Edit |

Think of cot as 1/tan, not cos/sin. In order for it to be defined, it has to work with BOTH of those definitions.

270 degrees = 3pi/2

tan(3pi/2) = -1/0 = undefined

1/undefined = undefined

By Madd87 (Madd87) on Friday, June 04, 2004 - 12:12 pm: Edit |

arctan's domain is -infinity to infinity, so the answer is obviously D

By Satchamp (Satchamp) on Friday, June 04, 2004 - 12:29 pm: Edit |

but i always thought that cot270=0

what does being defined really mean??

By Satchamp (Satchamp) on Friday, June 04, 2004 - 12:51 pm: Edit |

hey now.......cot of an angle = opposite/adjactent

....now wudnt that be equal to 0 .....at cot270

this is soo weird....

By Monoe (Monoe) on Friday, June 04, 2004 - 03:14 pm: Edit |

Cotangent is adjacent over opposite, not opposite over adjacent. It is the inverse of tangent.

By Joshjmgs (Joshjmgs) on Friday, June 04, 2004 - 03:17 pm: Edit |

madd, sorry but thats not true, arctan is only defined in the first and fourth quadrants.

and

arcsin is defined in the first are fourth quadrants

arccos is defined in the first and SECOND quadrants

By Joshjmgs (Joshjmgs) on Friday, June 04, 2004 - 03:19 pm: Edit |

" Cotangent is adjacent over opposite, not opposite over adjacent. It is the inverse of tangent."

Cotangeant the reciprocal on tangeant, the inverse of tangeant is arctan!

I dont mean to be so onol (o=>a) about the wording, but its kind of important to know the difference for the IIc.

By Satchamp (Satchamp) on Friday, June 04, 2004 - 04:14 pm: Edit |

isnt arctan different from Capital Arctan...

4get it.doesnt matter.......

so technically cot0 as well as cot 90 are undefined???

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