SOLUTION: If cos α = -24/25 and sin � = 4/5, α in quadrant II and � in quadrant I, what is cos(α + �)?

SOLUTION: If cos α = -24/25 and sin � = 4/5, α in quadrant II and � in quadrant I, what is cos(α + �)?

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Question 979153: If cos α = -24/25 and sin � = 4/5, α in quadrant II and � in quadrant I,
what is cos(α + �)?

Answer by anand429(138) (Show Source): You can put this solution on YOUR website!
cos a = -24/25
So, sin a =
= 7/25 (Taking positive value since, a is in quadrant II
Similarly,
cos b =
= 3/5 (since b in quadrant I)
cos(a+b) = cosa*cosb - sina*sinb
=
=
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