Bob
]]>Is this what the computer-wise generation has come to; that we cannot multiply out a simple expression ?
Go to it, boy wonder!
Bob
We're lazy.
]]>Is this what the computer-wise generation has come to; that we cannot multiply out a simple expression ?
Go to it, boy wonder!
Bob
]]>Just to show you it is possible
TrigReduce[2 Sin[B]^2 + 4 (Cos[B] Cos[B] - Sin[A] Sin[B])*Sin[A] Sin[B] + (Cos[A]^2 - Sin[A]^2) (Cos[B]^2 - Sin[B]^2) - 2 Sin[A] Cos[B]*2 Sin[B] Cos[B]]
I am getting cos(2A).
]]>I've ended up with cos(2A)
Bob
]]>That multiplication is tedious, I've not done it.(yet)
]]>Thought I'd made a mistake as my final simplified answer was a trig function of A, not a number.
Couldn't find a mistake so I set up the expression in Excel and tried a few angles. I consistently got the result I'd got by algebra and trig formulas.
Bob
]]>Bob
]]>You'll need a large sheet of paper or to write small.
Once you've multiplied this out, nearly everything cancels.
I converted all to sines with
But you can also simplify with the double angles instead.
Bob
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