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rollcast
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When I'm working out a maths or physics problem I always find myself questioning whether I should work out the equation as I go along or should I re arrange it and do it in one step with my calculator?
For example if I was to use the cosine rule for triangles,
a2=b2+c2-2bccosA
to solve a triangle for angle A with sides a, b and c as 20, 30 and 40 respectively.
Is this better written out as,
a2=b2+c2-2bccosA
202=302+402-2*30*40*cosA
400=900+1600-2400cosA
-2100=-2400cosA
7/8=cosA
A=cos-1(7/8)
A=29.0°(1D.P.)
or
a2=b2+c2-2bccosA
A=cos-1[itex]\left(\frac{b^{2}+c^{2}-a^{2}}{2bc}\right)[/itex]
A=cos-1[itex]\left(\frac{30^{2}+40^{2}-20^{2}}{2*30*40}\right)[/itex]
A=cos-1(7/8)
A=29.0(1D.P.)
Thanks
AL
For example if I was to use the cosine rule for triangles,
a2=b2+c2-2bccosA
to solve a triangle for angle A with sides a, b and c as 20, 30 and 40 respectively.
Is this better written out as,
a2=b2+c2-2bccosA
202=302+402-2*30*40*cosA
400=900+1600-2400cosA
-2100=-2400cosA
7/8=cosA
A=cos-1(7/8)
A=29.0°(1D.P.)
or
a2=b2+c2-2bccosA
A=cos-1[itex]\left(\frac{b^{2}+c^{2}-a^{2}}{2bc}\right)[/itex]
A=cos-1[itex]\left(\frac{30^{2}+40^{2}-20^{2}}{2*30*40}\right)[/itex]
A=cos-1(7/8)
A=29.0(1D.P.)
Thanks
AL
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