![leen2727](/avatars/10507.jpg)
leen2727
14.11.2020 •
Mathematics
Lol help please xxxx xd
Solved
Show answers
More tips
- C Computers and Internet Are there special gaming mice?...
- L Leisure and Entertainment When will Maslenitsa start?...
- F Food and Cooking Discovering the Mysterious Fruit of Feijoa...
- B Business and Finance How to Open an Online Store? A Detailed Guide for Beginners...
- W Work and Career How to Write a Resume That Catches the Employer s Attention?...
- C Computers and Internet Е-head: How it Simplifies Life for Users?...
- F Family and Home How to Choose the Best Diapers for Your Baby?...
- F Family and Home Parquet or laminate, which is better?...
- L Leisure and Entertainment How to Properly Wind Fishing Line onto a Reel?...
- L Leisure and Entertainment How to Make a Paper Boat in Simple Steps...
Answers on questions: Mathematics
- M Mathematics What is the y-intercept of this graph...
- M Mathematics 3) Hallar el conjunto solución de las siguientes ecuaciones y realizar la comprobación. a) 2x+7= -3 b) 7x-3= 9x+5 h) (2x-1)3= -125 c) 6x+7-2x = -x-8 i) 2 (x+7)2= 242 d) -9+6x=...
- S Social Studies Katy goes out on a first date with kurt, who wears axe ® cologne. after a great evening, katy and kurt “make out” for what seems like hours. the next day when katy is shopping...
- M Mathematics 5+x^2-7x in standard form...
- B Biology Adaptations shaped by natural selection: a) are magnified and enhanced through genetic drift b) are unlikely to be present in humans living in industrial societies c) may be...
Ответ:
1 | 2 2 4
2 | 0 1 3 6
3 | 4
key : 1 | 4 means 14
Ответ:
Correct cos(α - β) = 140/221
Step-by-step explanation:
cosα = ±√(1 - sin²α) => cosα = ±√(1 - (-5/13)²) = ±√(1 - (25/169)
cosα = ±√(169 -25)/169 = ± √144/169
cosα = ± 12/13 since it is given that α (alpha) ends in the third quadrant
we choose cosα = - 12/13
we know that is tanβ = sinβ/cosβ = - 8/15 or sinβ : cosβ = 8 : 15 =>
sinβ = 8k and cosβ = 15k where k is the coefficient of proportionality
we know the basic trigonometric equality
sin²β + cos²β = 1 when we replace the coefficients we get
(8k)² + (15k)² = 1 => 64k² + 225k² = 1 => 289k² = 1 => k² = 1/289 =>
k = 1/17 now we get sinβ and cosβ
since it is given that β (beta) ends in the second quadrant
sinβ = 8/17 and cosβ = - 15/17
As we know it is:
cos(α - β) = cosα cosβ + sinα sinβ = - 12/13 · (- 15/17) + (- 5/13) · 8/17 =>
cos(α - β) = 180/221 - 40/221 = 140/221
cos(α - β) = 140/221
God is with you!!!