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
Step-by-step explanation:
15 - c = 6
15 - 6 = c
9 = c
c = 9
4. 2b-6+3b=
5b-6=143
5b=143+6
5b=149
b=149
------
5
Answer:
Minimum - 8.1 inches
Maximum - 8.35 inches
Step-by-step explanation:
The specifications for manufacturing a steel rod stipulate that the length must be 8.225 ± 0.125 inches.
This means that the minimum length must not be 0.125 inches less than 8.225 inches and the maximum length must not be 0.125 inches greater than 8.225 inches.
The minimum length is therefore:
8.225 - 0.125 = 8.1 inches
The maximum length is therefore:
8.225 + 0.125 = 8.35 inches
