A . 3 sqrt 9
B . 2 sqrt 9
C.3 sqrt 27
D. 2 sqrt 27
Select one:
a. cos2x - sin2x - sin x
b. cos2x - sin3x
c. cos2x + sin2x + sin x
d. cos2x - 3 sin x
is the solution of the given equation.
To rewrite the expression cos 2x - sin x using only sin x and cos x, we can apply trigonometric identities.
Using the identity , we can rewrite the expression as:
Since,
Therefore, the correct answer is:
a.
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Perimeter of the figure PQR is 91.42 cm.
Perimeter of a straight sided figures or objects is the total length of it's boundary
Given figure PQR consists of an equilateral triangle and a semicircle.
Length of side of an equilateral triangle = 20 cm
Perimeter of equilateral triangle = sum of the length of three sides
Perimeter = 3 × 20 = 60 cm
Now circumference of a circle = 2πr, where r is the radius.
Here there is a semicircle, which is the half of the circle.
Circumference of semicircle = 2πr / 2 = πr
Here Diameter = 20 cm
Radius = 20 / 2 = 10 cm
Perimeter of semicircle = 10π = 31.42 cm
Total perimeter = 60 cm + 31.42 cm = 91.42 cm
Hence the total perimeter is 91.42 cm.
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