Perimeter ILL MARK BRAINLY
2 answers:
You might be interested in
Replace x with π/2 - x to get the equivalent integral
but the integrand is even, so this is really just
Substitute x = 1/2 arccot(u/2), which transforms the integral to
There are lots of ways to compute this. What I did was to consider the complex contour integral
where γ is a semicircle in the complex plane with its diameter joining (-R, 0) and (R, 0) on the real axis. A bound for the integral over the arc of the circle is estimated to be
which vanishes as R goes to ∞. Then by the residue theorem, we have in the limit
and it follows that
If we say that side "a" is the shortest (adjacent), side "b" is the second shortest (opposite), and side "c" is the longest (hypotenuse): then angle A would be 30°, angle B would be 60°, and angle C would be 90°
tan B = b/a
or
a tan B = b
they have 4 as the smallest value in all four options, so we know that a=4
4 tan 60° = b
tan 60° = √3
so, 4 tan 60° = 4√3
b=4√3
that leaves two options left, so now we find "c":
c^2 = (a^2) + (b^2)
OR
so a=4, b=4√3, and c=8
Making your answer B
tan B = b/a
or
a tan B = b
they have 4 as the smallest value in all four options, so we know that a=4
4 tan 60° = b
tan 60° = √3
so, 4 tan 60° = 4√3
b=4√3
that leaves two options left, so now we find "c":
c^2 = (a^2) + (b^2)
OR
so a=4, b=4√3, and c=8
Making your answer B