To evaluate the limit, we'll have to substitute x by the
value of x0, in the given expression.
lim
(4cosx-6sin^2x+3tan^2x) = 4cos 60 - 6*(sin 60)^2 + 3*(tan
60)^2
cos 60 = 1/2
sin 60 =
sqrt3/2
We'll raise to square both
sides:
(sin 60)^2 =
(sqrt3/2)^2
(sin 60)^2 =
3/4
tan 60 = sqrt 3
We'll
raise to square both sides:
(tan 60)^2 =
3
We'll substitute the values of the functions in the
expresison above:
lim (4cosx-6sin^2x+3tan^2x) = 4(1/2) -
6*(3/4) + 3*(3)
lim (4cosx-6sin^2x+3tan^2x) = 2 - 9/2 +
9
lim (4cosx-6sin^2x+3tan^2x) = (4 - 9 +
18)/2
lim (4cosx-6sin^2x+3tan^2x) = 13/2, for
x-> 60 degrees
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