I've answered your other question as well.
Step-by-step explanation:
Since the identity is true whether the angle x is measured in degrees, radians, gradians (indeed, anything else you care to concoct), I’ll omit the ‘degrees’ sign.
Using the binomial theorem, (a+b)3=a3+3a2b+3ab2+b3
⇒a3+b3=(a+b)3−3a2b−3ab2=(a+b)3−3(a+b)ab
Substituting a=sin2(x) and b=cos2(x), we have:
sin6(x)+cos6(x)=(sin2(x)+cos2(x))3−3(sin2(x)+cos2(x))sin2(x)cos2(x)
Using the trigonometric identity cos2(x)+sin2(x)=1, your expression simplifies to:
sin6(x)+cos6(x)=1−3sin2(x)cos2(x)
From the double angle formula for the sine function, sin(2x)=2sin(x)cos(x)⇒sin(x)cos(x)=0.5sin(2x)
Meaning the expression can be rewritten as:
sin6(x)+cos6(x)=1−0.75sin2(2x)=1−34sin2(2x)
Let x = the number of hours Eva needs to complete the job
and y = the number of hours Emily needs to complete the job
x = 6
1/x + 1/y = 1/4
(The amount of work Eva does in 1 hr + the amount of work Emily does in 1 hr should equal 1/4 of the total work)
1/6 + 1/y = 1/4
1/y = 1/12
y = 12 hours
Emily would take 12 hours to do it by herself.
The common denominator for 25 and 20 would be 100
25 x 4 = 100
20 x 5 = 100
Rewrite 14/25 as 14 x 4 / 25 x 4 = 56/100
Rewrite 11/20 as 11 x 5 / 20 x 5 = 55/100
14/25 is greater than 11/20
14/25 > 11/20
10x100=1,000 because it is ten hundreds so 1,000 is your answer