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my teacher is soooo bad he gave us a problem ... and he didn't even explain it ..... pls help me ..pls

here is the problem

1. sec(-2A)= csc 20 A

solve for A

pls help me

2006-07-13 01:26:02 · 13 answers · asked by Anonymous in Science & Mathematics Mathematics

13 answers

do your own math... lazy

2006-07-13 01:30:30 · answer #1 · answered by Anonymous · 0 0

Ans.: A=5 degrees

For a given right triangle, since sec and csc are co functions, their functions can only be equal if the sum of their respective angles representing the two acute angles is 90 degrees(meaning their angles are complementary angles).

solution:

-2A + 20A = 90
18A =90
A= 90/18
A=5 degrees

2006-07-13 03:21:21 · answer #2 · answered by baeyongmok 2 · 0 0

A equals 1

2006-07-13 01:30:52 · answer #3 · answered by Anonymous · 0 0

First, start off with the definition of sec and csc. sec (theta) = csc (pi/2 - theta). Therefore, you know that pi/2 + 2A = 20A. Use algebra to solve the rest.

2006-07-13 01:31:53 · answer #4 · answered by Anonymous · 0 0

This is a piece of cake:
sec(-2A)= 1/ (cos-2A) = 1/ cos2A
cosec 20A= 1/ sin20A

so cos2A= sin20A

and since cos (90-X) = sin X, so sin20A = cos (90-20A)
and then cos 2A= cos (90-20A)

2A = 90-20A
22A=90, so A will be 90/22= 4.09 approximately

2006-07-13 02:05:46 · answer #5 · answered by Anonymous · 0 0

Ah.....I remember problems like these. Hmmm.....you must change cosecant into a secant using the rules of tirg, then you can can cancel one of the two A's and use inverse trig to find the angle A.


O yeah..... YAHOO IS NOT MEANT FOR HOMEWROK

2006-07-13 01:31:20 · answer #6 · answered by bmg50barrett 2 · 0 0

Hey its the proper solution

sec(-2A)= sec(2A)

sec(2A)=csc20A
cos2A=sin20A
cos2a=cos(Pie/2-20A)
pie/2-20A= 2n(pie) +-(both + and -) 2A
Now u can easily manupulate taking + sign and then - sign.

For more email sg_a1@yahoo.com

2006-07-13 01:42:44 · answer #7 · answered by Need Help? 2 · 0 0

If i knew how to solve it i would have surely helped you!! But sorry, i cant!!!! Hate to say No to a girl like you!!!

2006-07-13 01:32:21 · answer #8 · answered by nice_libra_guy 6 · 0 0

I don't think YA is meant to help you with mundane maths homework.

2006-07-13 01:30:38 · answer #9 · answered by Son of Gap 5 · 0 0

Sorry

2006-07-13 01:29:55 · answer #10 · answered by mu_sa_kossan 5 · 0 0

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