Grade 11Trigonometry
Cos25°/sin70°sin85°+cos70°/sin25°sin85°+cos85°/sin25°sin70° Evaluate.
Cos25°/sin70°sin85°+cos70°/sin25°sin85°+cos85°/sin25°sin70° Evaluate.
1 Answer
Deepak Kumar Shringi
in the deno write
sin70=cos20 and sin85=cos5
now cos25=cos(20+5)=cos20cos5-sin20sin5
as the first term will become =1-tan5tan20 convert others as well in this way
sin70=cos20 and sin85=cos5
now cos25=cos(20+5)=cos20cos5-sin20sin5
as the first term will become =1-tan5tan20 convert others as well in this way
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