Answer:
see explanation
Step-by-step explanation:
Using the trigonometric identity
sin²x + cos²x = 1
Consider the left side
2cos²A - 1 ← replace 1 by sin²A + cos²A
= 2cos²A - ( sin²A + cos²A)
= 2cos²A - sin²A - cos²A
= cos²A - sin²A = right side ⇒ verified
Answer:
18: x=98 y=38
19: x=20 y=50
Step-by-step explanation:
To figure out figure 18 you would first figure out x and a triangle equals 180 so 180- (36+46) which is 180-82= 98 and then there are vertical angles between the right and left side so x is equal to one of the angles on the right so 98+44= 142 and 180-142= 38
Then to figure out figure 19 you would first find y by adding 39 and 91 to get 130 and 180-130=50 and then 180-91 (for the angle in the bottom right for the left triangle) is 89 so 89+71=160 and 180-160 is 20.
The answer to the question is D
The answer is the letter c. 3
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