Answer:
Cos b
Step-by-step explanation:
1/2[sin(a+b)+sin(a-b)]
1/2[sin a cos b +cos a sin b + sin A cos B - cos A sin B]
1/2[2sin a cos b]
sin a cos b
 
        
             
        
        
        
Answer:
   no
Step-by-step explanation:
Let f represent the fraction of C-14 remaining as a function of the time t in years. Since the half-life of C-14 is about 5570 years, we have ...
   f = (1/2)^(t/5570)
Taking the log and solving for t, we get ...
   log(f) = (t/5570)log(1/2)
   5570·log(f)/log(1/2) = t
Filling in the given value for f, the value of t we get is ...
   5570·log(0.65)/log(0.5) = t ≈ 3462
It appears the estimate of 4000 years is a bit high.
 
        
             
        
        
        
Midpiont=(_2+3\2), (4+_1/2)
=2/2,6/2
=1,3