You need
to evaluate the following limit such that:
`lim_(x->0) (sin^2
x)/(1-2sin((5pi)/6 - x)cos x) = (sin^2 0)/(1 - 2sin((5pi)/6)*cos 0)`
Since
`sin 0 = 0 ` and `cos 0 = 1` yields:
`lim_(x->0) (sin^2
x)/(1-2sin((5pi)/6 - x)cos x) = 0/(1 - 2sin((5pi)/6))`
You need to evaluate
`sin((5pi)/6) = sin(pi/3 + pi/2)`
Using the identity `sin(a+b) = sin a*cos b
+ sin b*cos a` yields:
`sin(pi/3 + pi/2) = sin(pi/3)cos(pi/2) +
sin(pi/2)cos(pi/3)`
Since `sin(pi/2) = 1` and `cos(pi/2) = 0` ...
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