Yahoo Answers is shutting down on 4 May 2021 (Eastern Time) and the Yahoo Answers website is now in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

Answer the following trigo question?

Refer to the problem

http://in.answers.yahoo.com/question/index;_ylt=Ah...

Solve for x if AD is the median and not an angle bisector.

3 Answers

Relevance
  • 9 years ago
    Favourite answer

    That means BD = x also

    Let the angle DAB = y, then from the right triangle ABD

    tany = x/29 ............ [1]

    Similarly, from the right triangle ABC

    tan(y + 20) = 2x/29

    ==> (tany + tan20)/(1 - tany * tan20) = 2x/29

    ==> substitute [1]:

    ==> (x/29 + tan20)/(1 - x/29 * tan20) = 2x/29

    ==> (x + 29tan20)/(29 - x * tan20) = 2x/29

    ==> 29(x + 29tan20) = 2x(29 - x * tan20)

    ==> (2 tan20) x^2 - 29x + 841tan20 = 0

    By Quadratic Formula

    x = (29 +/- √(841 - 6728tan²20))/(4 tan20)

    Since 841 - 6728tan²20 < 0, x is a complex number, but since x represents distance, x cannot be a complex number thus a contradiction, hence there'es no solution for x.

    Side note:

    For x to be real, angle CAD must be in the range of 0 to 7.1250163 degrees exclusive, if AB is still 29cm

    For x to be real, length AB must be in the range of 0 to 0.72429177 cm exclusive, if angle CAD is still 20 degrees.

  • 9 years ago

    CD=DB,let the angle BAD =y

    tany=x/29

    x=tany*29

    tan(20+y)=2x/29

    2x=tan(y+20)*29

    2x=[(tany+tan20)/(1-tanytan20)]*29

    2tany*29[1-tanytan20]=(tany+tan20)29

    2*29tany-2*29tan^2ytan20=tany*29+29tan20

    58tany-21.11tan^2y=29tany+10.56

    21.11tan^2y-29tany+10.56=0

    It has complex solutions.This means that with the angle 20 degrees AD cannot be a median.

  • Anonymous
    4 years ago

    because of the fact this may be a suited triangle, perspective CAB is 40 5 tiers. First, commence via getting the scale of Line advert. considering the fact that all of us understand that perspective CAB is 40 5 tiers, perspective DAB must be 40 5-20=25 tiers. To get the scale of Line advert, use: COS=adjoining/Hypotenuse, it somewhat is COS 25 tiers= 29/Line advert. COS 25=.906. We get .906AD=29; divide out the .906 and you get a length for Line advert as 29/.906= 32 cm. Now that we've the scale of line advert, we are able to be certain the scale of line CD via utilising: Tan=opposite/adjoining. Tan 20 tiers=Line CD/32. We proceed to get .364=Line CD/32. Multiply the two aspects via 32 to be certain the scale of Line CD and it measures .364*32= 11.sixty 5 cm.

Still have questions? Get answers by asking now.