Answer:
sin²x = (1 - cos2x)/2 ⇒ proved down
Step-by-step explanation:
∵ sin²x = (sinx)(sinx) ⇒ add and subtract (cosx)(cosx)
(sinx)(sinx) + (cosx)(cosx) - (cosx)(cosx)
∵ (cosx)(cosx) - (sinx)(sinx) = cos(x + x) = cos2x
∴ - cos2x + cos²x = -cos2x + (1 - sin²x)
∴ 1 - cos2x - sin²x = (1 - cos2x)/2 ⇒ equality of the two sides
∴ (1 - cos2x) - 1/2(1 - cos2x) = sin²x
∴ 1/2(1 - cos2x) = sin²x
∴ sin²x = (1 - cos2x)/2
Answer:
Im not 100 percent sure but I think you have to do this
Step-by-step explanation:
Add all numbers together to find total students
Then add the students in Chemistry and Physics and both together
Then find what that number is in percent to the total students
Let's use x to represent the number of hours since we don't know that.
750+250x<u><</u><u />2500
Subtract 750 from both sides.
250x<u><</u><u />1750
Divide both sides by 250.
x<u><</u><u />7
The most hours that they can do is 7, or it can be less.
So first we factor
9-t^2=difference of 2 perfect squares
a^2-b^2=(a-b)(a+b)
3^2-t^2=(3-t)(3+t)
t^2+t-12
factor by finding what 2 number add to get 1 and multiply to get -12
the numbers are -3 and 4
(t-3)(t+4)
[(3-t)(3+t)]/[(t-3)(t+4)] we can't factor out any further
if it was t^2-9 then we could go further but since it isn't this is the factored form
(<u><em>if</em></u> it was t^-9 then the answer would be (t+3)/(t+4))
