Friday, November 18, 2011

Answers to quiz 9

cosalpha = 1/5_____ sinalpha = 2sqrt(6)/5 _____ tanalpha = 2sqrt(6)

cosbeta = 2/5______ sinbeta = sqrt(21)/5 ______ tanbeta = sqrt(21)/2

cosgamma = 3/5___ singamma = 4/5 _________ tangamma = 4/3

cosdelta = 4/5 _____sindelta = 3/5 ___________ tandelta = 3/4 

cos(alpha + beta) = (2 - 6sqrt(14))/25
sin(alpha + beta) = (sqrt(21) + 4sqrt(6))/25
tan(alpha + beta) = 50(sqrt(21)+sqrt(6))/-500 = -(sqrt(21)+sqrt(6))/10

Corrected from original.  Thanks to Laura Hidrobo.

cos(beta - gamma) = (6 + 4sqrt(21))/25
sin(beta - gamma) = (3sqrt(21) - 8)/25
tan(beta - gamma) = 1 - sqrt(21)/6

Corrected from original.  Thanks to Bi Ting Zhen and Laura Hidrobo.

cos(gamma + delta) = 0
sin(gamma + delta) = 1

tan(gamma + delta) =undefined

The last one is this way because the angles are complementary.


6 comments:

  1. Hi, can you show me how you got the tan for the first and 2nd on the lower half of the quiz please. I am not getting your answer but instead the 25 in the demoninators cancel, and I am getting -500 in the denominator. In the numerator sqrt(21)+sqrt(6))/-10. The answer must be negative as well. Im confused with this.

    ReplyDelete
  2. Thanks, Laura. You were right and I was wrong. I've fixed the post and given you two points extra credit on homework 11.

    ReplyDelete
  3. Hi, I have a question about the 2nd tangent problem. I am getting (negative sqrt 21)/6 +1 your getting a positive. Where am I wrong?

    ReplyDelete
  4. Hi, Laura. I went too fast again. The simplest way to write it is 1 - sqrt(21)/6.

    One more extra credit point for you.

    ReplyDelete
  5. Thanks :) I was reviewing it and reviewing it LOL

    ReplyDelete
  6. This comment has been removed by a blog administrator.

    ReplyDelete