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2 answers:
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Answer:
Step-by-step explanation:
Using the difference formula for cosine and the exact values
cos45° = sin45° = , cos30° =
, sin30° =
cos(a - b) = cosacosb + sinasinb
Note 15° = 45° - 30°, thus
cos15°
= cos(45 - 30)°
= cos45°cos30° + sin45°sin30°
= ( ×
) + (
×
)
= +
=
Answer:
i. + 26x + 144 - 299 = 0
ii. x = 5
Step-by-step explanation:
The area of the figure = 299 cm²
The figure has a shape of a rectangle, so that;
Area of rectangle = length x width
length of the figure = 18 + x
width of the figure = 8 + x
Area of the figure = (18 + x) x (8 + x)
299 = (18 + x) x (8 + x)
299 = + 26x + 144
+ 26x + 144 - 299 = 0
+ 26x - 155 = 0
applying the trigonometric formula;
x = (-b ± ) ÷ 2a
= (-26 ± ) ÷ 2
= (-26 ± ) ÷ 2
= (-26 ± ) ÷ 2
= (-26 ± 36) ÷ 2
x = (-26 + 36) ÷ 2 OR x = (-26 -36) ÷ 2
= 10 ÷ 2 OR -62 ÷ 2
= 5 OR -31
Thus, x = 5