The correct question is
Use the given information to find the exact value of the expression. sin α = 21/29, α lies in quadrant II, and cos β = 15/17, β lies in quadrant I Find sin (α - β).
we know that
sin(α − β<span>) = </span>sin α cos β − cos α sin β
α lies in quadrant II
so
cos α is negative
sin α is positive
β lies in quadrant I
so
cos β is positive
sin β is positive
step 1
find sin β
cos β=15/17
sin² β+cos² β=1-----------> sin² β=1-cos² β----> sin² β=1-(15/17)²
sin² β=1-225/289-----> 64/289
sin β=8/17
step 2
find cos α
sin α = 21/29
cos² α + sin² α=1----> cos² α=1-sin² α---> cos² α=1-(21/29)²---> 1-441/841
cos² α=400/841------> cos α=-20/29 (remember cos α is negative)
step 3
find sin(α − β)
sin α = 21/29 cos α=-20/29
sin β=8/17 cos β=15/17
sin(α − β) = [21/29]*[15/17] − [-20/29*]*[8/17]
sin(α − β) = [315/493] − [-160/493]
sin(α − β) = 475/493
the answer is
sin(α − β) = 475/493
The correct answer should be A.
Your answer is c. i know this because this was the exact same question i did yesterday and i got 100%
Answer:
Solution given:
r=3km
area of sector bounded by a 90° arc=90°/360°*πr²
=¼*π*3²
=<u>9/4 π or 7.068km²</u>
is a required answer
