Evaluate 14- 2xy when x=6 and y=2
2 answers:
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9514 1404 393
Answer:
77/85
Step-by-step explanation:
<u>Given</u>:
cos(A) = 4/5
sin(B) = 15/17
<u>Find</u>:
cos(A-B)
<u>Solution</u>:
From your knowledge of Pythagorean triples, you know that one of them is (3, 4, 5) and another is (8, 15, 17). Using your imagination, or by drawing the triangles, you can determine the needed trig functions to be ...
sin(A) = 3/5
cos(B) = 8/17
__
Alternatively, you can use the Pythagorean identity to find ...
sin(A) = √(1 -cos²(A)) = √(1 -(4/5)²) = √(9/25) = 3/5
cos(B) = √(1 -sin²(B)) = √(1 -(15/17)²) = √(64/289) = 8/17
__
Then application of the angle difference formula is straightforward.
cos(A -B) = cos(A)cos(B) +sin(A)sin(B)
cos(A -B) = (4/5)(8/17) +(3/5)(15/17) = (32 +45)/85
cos(A -B) = 77/85
_____
Some graphing calculators can express the result ...
cos(arccos(4/5) -arcsin(15/17)) ≈ 0.90588235294
... as the fraction 77/85
Answer:
$1.46
Step-by-step explanation:
To find the original price of the game, write a proportion. $1.54 is the amount after a 5.5% tax rate. This means he paid 105.5% on the original price.
Find y by cross multiplying numerator and denominator of each fraction.
1.54(100) = 105.5y
154 = 105.5y
1.46 = y