y = arctan(x/2) - 1/(2(x^2+4)) Find the derivative of the function

The derivative of y with respect to is denoted as y' or (dy)/(dx) .
 For the given equation: y = arctan(x/2) -1/(2(x^2+4)) ,
we may apply the basic property of derivative:
d/(dx) (u-v) =d/(dx) (u) - d/(dx)(v)
 
Then the derivative of y will be:
y' = d/(dx)(arctan(x/2) -1/(2(x^2+4)))
y' =d/(dx)(arctan(x/2)) - d/(dx)( 1/(2(x^2+4)))
To find the derivative of the first term: d/(dx)(arctan(x/2)) , recall the basic derivative formula for inverse tangent as:
d/(dx) (arctan(u)) = ((du)/(dx))/(1+u^2)
With u = x/2 and du=(1/2) dx or (du)/(dx) =1/2 , we will have:
d/(dx)(arctan(x/2)) = (1/2) /(1+(x/2)^2)
                           = (1/2) /(1+(x^2/4))
Express the bottom as one fraction:
d/(dx)(arctan(x/2)) = (1/2) /((x^2+4)/4)
Flip the bottom to proceed to multiplication:
d/(dx)(arctan(x/2)) = 1/2*4/(x^2+4)
                          = 4/(2(x^2+4))
                          =2/(x^2+4)
 
For the derivative of the second term: d/(dx)(1/(2(x^2+4))) , we can rewrite it using the basic property of derivative: d/(dx) (c*f(x)) = c* d/(dx) f(x) where c is constant.
d/(dx)(1/(2(x^2+4))) = (1/2) d/(dx)(1/(x^2+4))
Then apply the Quotient Rule for derivative: d/(dx) (u/v)= (u' * v- v'*u)/v^2 on  d/(dx)(1/(2(x^2+4))) .
We let:
u = 1 then    u' = 0
v = x^2+4 then v'=2x
v^2= (x^2+4)^2
Applying the Quotient rule, we get:
d/(dx)(1/(2(x^2+4))), = (0*(x^2+4)-(1)(2x))/(x^2+4)^2
                         =(0-2x)/ (x^2+4)^2
                         =(-2x)/ (x^2+4)^2
 
Then (1/2) * d/(dx)(1/(x^2+4)) =(1/2) * (-2x)/ (x^2+4)^2
                                              = -x/ (x^2+4)^2
 For the complete problem: 
y' =d/(dx)(arctan(x/2)) - d/(dx)( 1/(2(x^2+4)))
y' =2/(x^2+4) + x/ (x^2+4)^2
 

Comments

Popular posts from this blog

How does Bilbo show leadership and courage in The Hobbit?

In “Goodbye to All That,” Joan Didion writes that the “lesson” of her story is that “it is distinctly possible to remain too long at the fair.” What does she mean? How does the final section of the essay portray how she came to this understanding, her feelings about it, and the consequences of it?

Why does the poet say "all the men and women merely players"?