We know that
if cos x is positive
and
sin x is negative
so
the angle x belong to the IV quadrant
cos x=5/13
we know that
sin²x+cos²x=1-------> sin²x=1-cos²x------> 1-(5/13)²---> 144/169
sin x=√(144/169)-------> sin x=12/13
but remember that x is on the IV quadrant
so
sin x=-12/13
Part A) <span>cos (x/2)
cos (x/2)=(+/-)</span>√[(1+cos x)/2]
cos (x/2)=(+/-)√[(1+5/13)/2]
cos (x/2)=(+/-)√[(18/13)/2]
cos (x/2)=(+/-)√[36/13]
cos (x/2)=(+/-)6/√13-------> cos (x/2)=(+/-)6√13/13
the angle (x/2) belong to the II quadrant
so
cos (x/2)=-6√√13/13
the answer Part A) is
cos (x/2)=-6√√13/13
Part B) sin (2x)
sin (2x)=2*sin x* cos x------> 2*[-12/13]*[5/13]----> -120/169
the answer Part B) is
sin(2x)=-120/169
Answer: the farmer has 19 cows.
Step-by-step explanation:
Let x represent the number of cows that the farmer has.
Let y represent the number of chicken that the farmer has.
The farmer has a total of 40 animals. It means that
x + y = 40
A cow has 4 legs. A chicken has 2 legs. One day he counts the legs of all his animals and realizes he has a total of 118 legs. It means that
4x + 2y = 118- - - - - - - - 1
Substituting x = 40 - y into equation 1, it becomes
4(40 - y) + 2y = 118
160 - 4y + 2y = 118
- 4y + 2y = 118 - 160
- 2y = - 42
y = - 42/ - 2
y = 21
x = 40 - y = 40 - 21
x = 19
Answer:
4.2 × 
Step-by-step explanation:
2.1 ×
× 2 × 
2.1 + 2 = 4.2
2 - 3 = - 1
4.2 × 
Answer:
This is the identity property. So the answer is C
Step-by-step explanation:
The identity property is the rule that any real number multiplied by one will still be that number. Hope this helped :)