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 May 25th, 2019, 02:39 PM #1 Member   Joined: Jan 2019 From: tornto Posts: 48 Thanks: 0 Tan inverse 1)- if tanC= -0.6687 find C to the nearest degree C? MY ANSWER -33.77064668 OR SHOULD IT BE -33.80 2)- COS 59 = X/36 X = (COS 59)* (36) = 18.5713707 CORRECT?? 3)- sin 25= 34/x x= (sin 25) * (34) = 14.3690209 correct ??? thanks Last edited by yorkmanz; May 25th, 2019 at 02:52 PM. May 25th, 2019, 03:15 PM   #2
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Quote:
 Originally Posted by yorkmanz 1)- if tanC= -0.6687 find C to the nearest degree C? MY ANSWER -33.77064668 OR SHOULD IT BE -33.80 2)- COS 59 = X/36 X = (COS 59)* (36) = 18.5713707 CORRECT?? 3)- sin 25= 34/x x= (sin 25) * (34) = 14.3690209 correct ??? thanks
All correct! The first one says to the nearest degree, which would be -34 degrees. (Also note that this is a reference angle. So we would have another solution 180 - 33.77.)

-Dan May 25th, 2019, 03:32 PM   #3
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 Originally Posted by topsquark All correct! The first one says to the nearest degree, which would be -34 degrees. (Also note that this is a reference angle. So we would have another solution 180 - 33.77.) -Dan
Question 1) if tanC= -0.6687 find C to the nearest degree C, C is between 0 and 180 degree?

like that

tanC = - 0.6687

tanC IS NEGATIVE

SO MY ANSWER SHOULD BE BETWEEN 90-180

tan(90+A) = -tanA

tanC = tan(90+A) = -0.6687

tan(90+A) = -tanA

-tanA = -0.6687 remove negatives

A = tan^(-1) 0.6687

A = 33.77

C = 90+33.77 = 123.77 degree CORRECT???? May 25th, 2019, 03:37 PM #4 Member   Joined: Jan 2019 From: tornto Posts: 48 Thanks: 0 for question 3) 3)- sin 25= 34/x sin5= .423 .423=34/x .423x=34 x=34/.423 x=80.37 correct? May 25th, 2019, 05:05 PM   #5
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Quote:
 Originally Posted by yorkmanz X = (COS 59)* (36) = 18.5713707 CORRECT?
No. cos(59$^\circ\!$)*36 = 18.5413707 (approximately).

Quote:
 Originally Posted by yorkmanz tan(90+A) = -tanA
That's incorrect. As tan(180$^\circ\!$ - C) = -tan C,
you want 180$^\circ\!$ - 33.77$^\circ\!$... = 146.23$^\circ\!$ approximately (or 146$^\circ\!$ if rounded to the nearest degree).

Quote:
 Originally Posted by yorkmanz 3)- sin 25= 34/x sin5= .423 .423=34/x .423x=34 x=34/.423 x=80.37 correct?
No. You need better accuracy. Also, you typed sin5, but meant sin 25.
sin(25$^\circ\!$) = 0.42261826174...
so x = 34/0.42261826174... = 80.450853827... = 80.45 approximately. Tags inverse, tan Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Similar Threads Thread Thread Starter Forum Replies Last Post SeanDaniel Linear Algebra 2 November 15th, 2014 03:21 PM cheyb93 Calculus 1 February 12th, 2013 08:45 PM jaredbeach Algebra 1 November 17th, 2011 11:58 AM JOANA Abstract Algebra 0 March 18th, 2011 06:29 AM azerty Calculus 1 December 31st, 1969 04:00 PM

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