Answer:
D. Pythagorean
Step-by-step explanation:
Given the identity
cos²x - sin²x = 2 cos²x - 1.
To show that the identity is true, we need to show that the left hand side is equal to right hand side or vice versa.
Starting from the left hand side
cos²x - sin²x ... 1
According to Pythagoras theorem, we know that x²+y² = r² in a right angled triangle. Coverting this to polar form, we have:
x = rcostheta
y = rsintheta
Substituting into the Pythagoras firnuka we have
(rcostheta)²+(rsintheta)² = r²
r²cos²theta+r²sin²theta = r²
r²(cos²theta+sin²theta) = r²
(cos²theta+sin²theta) = 1
sin²theta = 1 - cos²theta
sin²x = 1-cos²x ... 2
Substituting equation 2 into 1 we have;
= cos²x-(1-cos²x)
= cos²x-1+cos²x
= 2cos²x-1 (RHS)
This shows that cos²x -sin²x = 2cos²x-1 with the aid of PYTHAGORAS THEOREM
Answer:
28 cubs
Step-by-step explanation:
Since one and a half bear produces one and a half cub, then 6 bears will produce 6 cubs in one and a half days.
We need to find 7 days, though but we have the rate for six bears for 1.5 days which 6 bears one a half day.
What is the rate for a day?
6/1.5 =
6 bears produce 4 cubs a day.
Now just do 4 x 7
4 x 7 = 28
Therefore, 6 bears produce 28 cubs in 7 days.
The perimeter of a rectangle is twice the sum of length and width, so the sum of length and width is half the perimeter, 10 3/4 ft.
The width will be the difference between this and the length, hence 5 1/2 ft.
The area is the product of length and width.
A = length×width
A = (5.25 ft)×(5.5 ft) = 28.875 ft²
The area of the sandbox is 28 7/8 ft².
Ten times the sum of two and five tenths and thirteen and 5 tenths.
