The answer tour question is D
        
                    
             
        
        
        
Correct question with correct options has been attached
Answer:
37
Step-by-step explanation:
Let C represent those dressed as heroes and let B represent those wearing mask
Thus;
n(C) = 39
n(D) = 45
We are told that 21 entrants were dressed as heroes wearing a mask. 
Thus; n(C n D) = 21
We are also told that there were a total of 100 entries. 
Thus, n(T) = 100
Now, number of entrants neither dressed as heroes nor wearing a mask is given by;
n(T) - n(C u D) 
n(C u D) = n(C) + n(D) - n(C n D) 
n(C u D) = 39 + 45 - 21
n(C u D) = 63
Thus;number of entrants neither dressed as heroes nor wearing a mask is: 100 - 63 = 37
 
        
             
        
        
        
Answer:
Equation of tangent plane to given parametric equation is:

Step-by-step explanation:
Given equation
        ---(1)
---(1)
Normal vector  tangent to plane is:


Normal vector  tangent to plane is given by:
![r_{u} \times r_{v} =det\left[\begin{array}{ccc}\hat{i}&\hat{j}&\hat{k}\\cos(v)&sin(v)&0\\-usin(v)&ucos(v)&1\end{array}\right]](https://tex.z-dn.net/?f=r_%7Bu%7D%20%5Ctimes%20r_%7Bv%7D%20%3Ddet%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D%5Chat%7Bi%7D%26%5Chat%7Bj%7D%26%5Chat%7Bk%7D%5C%5Ccos%28v%29%26sin%28v%29%260%5C%5C-usin%28v%29%26ucos%28v%29%261%5Cend%7Barray%7D%5Cright%5D)
Expanding with first row

at u=5, v =π/3
                    ---(2)
 ---(2)
at u=5, v =π/3 (1) becomes, 
                  
                 
                 
From above eq coordinates of r₀ can be found as:
             
From (2) coordinates of normal vector can be found as
              
   
Equation of tangent line can be found as:
   
 
        
             
        
        
        
Since the absolute value of any number is always positive, the absolute value of -2 2/3 is 2 2/3.
Hope this helps!