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
-3(x+3)= -3(x+1)-5
-3x+9=-3x+3-5
so you would have just distributed then you combine like terms and get
-3x+9=-3x-2
then add two to both sides and get
-3x+9=-3x-2
-3x+2=-3x+2
-3x+11=-3x
+3x+11=+3x
0x+11=0x
so 11+0x
divide both by zero and you get x+0
Answer:
Step-by-step explanation:
Put the values of x from the table to the equation:
From the comment.
Convert the equation:
<em>multiply both sides by 4</em>
Put the values of y from the table to the equation:
Answer:
14. :D
Step-by-step explanation:
