cos A = 12/13
sec A = 1/cos A = 13/12
sin A =sqrt ( 1 - cos^2 A) = sqrt (169/169 - 144/169) = sqrt( 25/169) =5/13
13/12 + 5/13 = (169 +60) / 156 = 229/156
If 13cos A=12,find the value of sec A + sin A
2 answers
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13cos A=12
cosA = 12/13, recognize the right-angled triangle with sides 5-12-13
so sinA = 5/13
since cosA is positive,
A could be in quad I or IV
if A is in I, cosA = 12/13, sinA = 5/13,
then sec A + sin A = 13/12 + 5/13 = 228/156
If A is in IV, cosA = 12/13, sinA = -5/13, then
secA + sinA = 13/12 - 5/13 = 109/156
13cos A=12
cosA = 12/13, recognize the right-angled triangle with sides 5-12-13
so sinA = 5/13
since cosA is positive,
A could be in quad I or IV
if A is in I, cosA = 12/13, sinA = 5/13,
then sec A + sin A = 13/12 + 5/13 = 228/156
If A is in IV, cosA = 12/13, sinA = -5/13, then
secA + sinA = 13/12 - 5/13 = 109/156
0 answers