Erin loves to play sports! She has earned 333 tennis trophies, 444 basketball trophies, 777 soccer trophies, and 111 volleyball
2 answers:
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Answer:
Step-by-step explanation:
The equation for the amount of money in an account after a certain amount is deposited and compounded after t years once per year is
Our A(t) = 33800, P = 4400, r = .075 and we are looking for t. Filling in:
and
Begin by dividing both sides by 4400 to get
The only way to move that t our from its current position as an exponent is to take the natural log of both sides and follow the rules for natural logs:
The power rule of natural logs says we can move that exponent down in front, giving us:
Divide both sides by ln(1.075) to get
Do this division on your calculator to get
t = 28.2 years
Answer:
So 67 degrees is one value that we can take the sine of such that is equal to cos(23 degrees).
(There are more values since we can go around the circle from 67 degrees numerous times.)
Step-by-step explanation:
You can use a co-function identity.
The co-function of sine is cosine just like the co-function of cosine is sine.
Notice that cosine is co-(sine).
Anyways co-functions have this identity:
or
You can prove those drawing a right triangle.
I drew a triangle in my picture just so I can have something to reference proving both of the identities I just wrote:
The sum of the angles is 180.
So 90+x+(missing angle)=180.
Let's solve for the missing angle.
Subtract 90 on both sides:
x+(missing angle)=90
Subtract x on both sides:
(missing angle)=90-x.
So the missing angle has measurement (90-x).
So cos(90-x)=a/c
and sin(x)=a/c.
Since cos(90-x) and sin(x) have the same value of a/c, then one can conclude that cos(90-x)=sin(x).
We can do this also for cos(x) and sin(90-x).
cos(x)=b/c
sin(90-x)=b/c
This means sin(90-x)=cos(x).
So back to the problem:
cos(23)=sin(90-23)
cos(23)=sin(67)
So 67 degrees is one value that we can take the sine of such that is equal to cos(23 degrees).
