磷酸锰铁锂电池:cos10cos30cos50cos70

=sin70cos10cos30cos50cos70/sin70
=2sin140cos30cos50cos10/sin70
=2sin50cos30cos50cos10/sin70
=4sin100cos30cos10/sin70
=4sin10cos30cos10/sin70
=8sin20cos30/sin70
=8*sqrt(3)/2*sin20/sin70
=4*sqrt(3)*tan20

=sin70cos10cos30cos50cos70/sin70
=1/2sin140cos30cos50cos10/sin70
=1/2sin50cos30cos50cos10/sin70
=1/4sin100cos30cos10/sin70
=1/4sin10cos30cos10/sin70
=1/8sin20cos30/sin70
=1/2sin20cos10cos50cos70/sin70
=1/2sin20sin80sin40sin20/sin70
以下的我简化不出太好的结果了。

=sin70cos10cos30cos50cos70/sin70
=0.5*sin140cos30cos50cos10/sin70
=0.5*sin50cos30cos50cos10/sin70
=0.25*sin100cos30cos10/sin70
=0.25*sin10cos30cos10/sin70
=0.125*sin20cos30/sin70
=0.125*sqrt(3)/2*sin20/sin70
=0.0625*sqrt(3)*tan20
≈0.108253*tan20
≈0.0394

0.98480775301220805936674302458952*0.86602540378443864676372317075294*0.64278760968653932632264340990726*0.34202014332566873304409961468226=0.18749999999999999999999999999962