Answer:
[tex]\frac{x}{2} *\sqrt{x^{2} +4}[/tex] +[tex]\frac{1}{2}[/tex]*LN(|[tex]\frac{x+\sqrt{x^{2} +4} }{2}[/tex]|) +C
Step-by-step explanation:
we will have to do a trig sub for this
use x=a*tanθ for sqrt(x^2 +a^2) where a=2
x=2tanθ, dx= 2 sec^2 (θ) dθ
this turns [tex]\int\limits {\sqrt{x^{2}+4 } } \, dx[/tex] into integral(sqrt( [2tanθ]^2 +4) * 2sec^2 (θ) )dθ
the sqrt( [2tanθ]^2 +4) will condense into 2sec^2 (θ) after converting tan^2(θ) into sec^2(θ) -1
then it simplifies into integral(4*sec^3 (θ)) dθ
you will need to do integration by parts to work out the integral of sec^3(θ) but it will turn into (1/2)sec(θ)tan(θ) + (1/2) LN(|sec(θ)+tan(θ)|) +C
then you will need to rework your functions of θ back into functions of x
tanθ will resolve back into [tex]\frac{x}{2}[/tex] (see substitutions) while secθ will resolve into [tex]\frac{\sqrt{x^{2} +4} }{2}[/tex]
sec(θ)=[tex]\frac{\sqrt{x^{2} +4} }{2}[/tex] is from its ratio identity of hyp/adj where the hyp. is [tex]\sqrt{x^{2} +4}[/tex] and adj is 2 (see tan(θ) ratio)
after resolving back into functions of x, substitute ratios for trig functions:
= [tex]\frac{x}{2} *\sqrt{x^{2} +4}[/tex] + [tex]\frac{1}{2}[/tex]*LN(|[tex]\frac{x+\sqrt{x^{2} +4} }{2}[/tex]|) +C
