Answer:
I do not know the answer to this question
Step-by-step explanation:
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: 18
Step-by-step explanation:
this is because complementary angles add up to 90 degrees so you would just subtract 72 from 90 to get your answer :)
Jenna has $43 and Heidi has $17.
Step-by-step explanation:
Total amount = $60
Let,
Amount of Jenna = x
Amount of Heidi = y
According to given statement;
x+y=60 Eqn 1
x=2y+9 Eqn 2
Putting value of Eqn 2 in Eqn 1;
Dividing both sides by 3,
Putting y=17 in Eqn 2
Jenna has $43 and Heidi has $17.
Keywords: linear equations, substitution method
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