Cos(2x) = cos^2(x) - sin^2(x) - cos(x)
but sin^2(x) = 1 - cos^2(x)
cos(2x) - cos(x) = cos^2(x) - (1 - cos^2(x) ) - cos(x)
cos(2x) - cos(x) = cos^2(x) - 1 + cos^2(x) - cos(x)
cos(2x) - cos(x) = 2cos^2(x) - 1 - cos(x)
cos(2x) - cos(x) = (2cos(x) + 1)(cos(x) - 1)
I think this is what you have asked for.
Answer:
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Step-by-step explanation:
The value of k is
<h3>How to solve the simultaneous equation?</h3>
Given:
x-y=k.............(eq i)
2x²+y²-15..............(eq ii)
We would make y the subject formula in eq ii
2x²+y²-15= 0
2x² + y²= 15
y²= 15-2x²
y= 
...........(eq iii)
Substitute the value of y into eq i
x-(= k
x- (
= k
k=
Read more about simultaneous equations here:
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Answer:
The values of x and y are x = 6 and y = 9Step-by-step explanation:
MNOP is a parallelogram its diagonal MO and PN intersected at point A
In any parallelogram diagonals:
Bisect each other
Meet each other at their mid-point
In parallelogram MNOP
∵ MO and NP are its diagonal
∵ MO intersect NP at point A
- Point A is the mid-point pf them
∴ MO and NP bisect each other
∴ MA = AO
∴ PA = AN
∵ MA = x + 5
∵ AO = y + 2
- Equate them
∴ x + 5 = y + 2 ⇒ (1)
∵ PA = 3x
∵ AN = 2y
- Equate them
∴ 2y = 3x
- Divide both sides by 2
∴ y = 1.5x ⇒ (2)
Now we have a system of equations to solve it
Substitute y in equation (1) by equation (2)
∴ x + 5 = 1.5x + 2
- Subtract 1.5x from both sides
∴ - 0.5x + 5 = 2
- Subtract 5 from both sides
∴ - 0.5x = -3
- Divide both sides by - 0.5
∴ x = 6
- Substitute the value of x in equation (2) to find y
∵ y = 1.5(6)
∴ y = 9
The values of x and y are x = 6 and y = 9
Answer:
The inequality for 
is:
Step-by-step explanation:
Given:
Width of rectangle = 3 ft
Height or length of rectangle = 
ft
Perimeter is at least 300 ft
To write an inequality for .
Solution:
Perimeter of a rectangle is given as:
⇒ 
where 
represents length of the rectangle and 
represents the width of the rectangle.
Plugging in the given values in the formula, the perimeter can be given as:
⇒ 
Using distribution:
⇒ 
Simplifying.
⇒ 
The perimeter is at lest 300 ft. So, the inequality can be given as:
⇒ 
Solving for
Subtracting both sides by 16.
⇒ 
⇒ 
Dividing both sides by 2.
⇒ 
⇒ (Answer)
