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:
This is already factored for the zeros of the quadratic. If x - 5 = 0 and x - 20 = 0 then x = 5 and 20. The ball was kicked 5 feet out and landed at 20 feet down the field. The difference is 15 feet. That's how far the ball traveled from its initial position on the ground to its landing place.
So 15 feet from where it was kicked.
The answer I believe is -2. Thank you come again
I believe that the answer is 100,000
Cos 45=7 under root 2 /AB
1 / Under root 2 = 7 under root 2 / AB
AB=14
Ans = 14(b)
