Answer:
108
Step-by-step explanation:
3 ft. squared is 9 ft.
9x12=108
∛-512 = -8 . . . . . . . . . . matches the 3rd selection
The tens digit is 8 more than the ones digit. There isn't any zeros.
The maximum digit is 9 because 10 would be 2 digits, 1 and 0.
So say the tens digits is 9.
9 _
The ones digit is 8 less so 9-8 = 1
9 1
There isn't any zeros which is correct.
The answer is 91.
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