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
-84 - 55
= -139
Here both have same sign (-) so u add and put the common sign(-) ....
So the answer is option B ( -139)...
Hope it helps!!!
This = - 8 * 1/2 * sqrt2*sqrt32
= -4 * sqrt64
= -4 * 8
= -32 (answer) Its B
Answer:
Below in bold.
Step-by-step explanation:
Radius of the pizza = 1/2 * 8 = 4 in.
Area of the whole pizza = π r^2
= π * 4^2
= 8 π
So if you take 1/8 away
the area left = 7/8 * 8 * π
= 7π
Taking π to be 22/7:
= 7 * 22/7
= approximately 22 in^2.
