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:
given that a batch of 140 semiconductor chips is inspected by choosing a sample of 5 chips without replacement.
10 chips do not conform to customer requirements.
i.e. out of 140 chips 10 are defective and 130 are good
a) 5 chips can be selected form 140 chips in 140C5 ways
= 416965528
b) For containing exactly one non conforming chip we have one selected from 10 and other 4 selected from 130
No of ways = 
c) For atleast one nonconforming chip we can calculate as total - no non conforming
i.e. 
Answer:
B
Step-by-step explanation:
5(2x+4)=30
10x+20=30
10x=10
x=1
Answer:
x = 55
Step-by-step explanation:
In a rhombus, each diagonal bisects a pair of opposite angles.
For this parallelogram t be a rhombus, the angles with measures 2x - 40 and x + 15 must be congruent.
2x - 40 = x + 15
Subtract x from both sides.
x - 40 = 15
Add 40 to both sides.
x = 55
