pembuktian identitas trigonometi : sec A . tan (90derajat - A) = cosec A

Identitas
sec A  = 1/cos A
cosec  A = 1/sin A
tan (90-A) = cot A
cotA = cos A /sin A
.
sec A. tan (90  - A )  = cosec A
ruas kiri  = ruas kanan

sec A. tan(90-A) =
= 1/cos A . cot A
= 1/cos A . cos A/sin A
= 1/sin A
= cosec A
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