Answer:
Step-by-step explanation:
Use the half angle identity for cosine:
cos(x/2)=+ or - sqrt(1+cos(x))/sqrt(2)
I'm going to figure out the sign part first for cos(x/2)...
so x is in third quadrant which puts x between 180 and 270
if we half x, x/2 this puts us between 90 and 135 (that's the second quadrant)
cosine is negative in the second quadrant
so we know that
cos(x/2)=-sqrt(1+cos(x))/sqrt(2)
Now we need cos(x)... since we are in the third quadrant cos(x) is negative...
If you draw a reference triangle sin(x)=3/5 you should see that cos(x)=4/5 ... but again cos(x)=-4/5 since we are in the third quadrant.
So let's plug it in:
cos(x/2)=-sqrt(1+4/5)/sqrt(2)
No one likes compound fractions (mini-fractions inside bigger fractions)
Multiply top and bottom inside the square roots by 5.
cos(x/2)=-sqrt(5+4)/sqrt(10)
cos(x/2)=-sqrt(9)/sqrt(10)
cos(x/2)=-3/sqrt(10)
Rationalize the denominator
cos(x/2)=-3sqrt(10)/10
Answer:
Step-by-step explanation:
oh gosh
im sorry but idk how to solve that, mabye if i say you are smart you will be motivated?
9514 1404 393
Answer:
A) Enterprise: E(x) = 50 +0.25x; Hertz: H(x) = 30 +0.45x
B) see attached graph
Step-by-step explanation:
A) We choose to compare Hertz (lowest daily charge) and Enterprise (lowest mileage charge). In each case, the total charge will be the sum of the daily charge and the product of the mileage charge and number of miles (x).
Enterprise: E(x) = 50 +0.25x
Hertz: H(x) = 30 +0.45x
Answer:
the solution is (-1, 2)
Step-by-step explanation:
Let's solve the system
(3x + 4y = 5)
(2x - 3y = -8)
using the method of elimination by addition and subtraction. Notice that if we multiply all terms of the first equation by 3 and all terms of the second by 4, y as a variable will temporarily disappear:
9x + 12y = 15
8x - 12y = -32
-----------------------
17x = - 17, so x = -1.
Replacing x in the second equation by -1, we get:
2(-1) - 3y = -8, or
2 + 3y = 8,
or 3y = 6. Thus, y = 2, and the solution is (-1, 2).
