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September 21, 2014

September 21, 2014

Posted by **bhavya** on Sunday, August 21, 2011 at 11:25am.

- trig -
**Reiny**, Sunday, August 21, 2011 at 11:51amFrom the first:

cosŲ - 1 = 4sinŲ

square both sides

cos^2 Ų - 2cosŲ + 1 = 16sin^2 Ų

cos^2 Ų - 2cosŲ + 1 = 16(1 - cos^2 Ų)

17cos^2 Ų - 2cosŲ - 15 = 0

(17cosŲ + 15)(cosŲ - 1)

cosŲ = -15/17 or cosŲ = 1

case1: cosŲ = -15/17

then sinŲ = 8/17 (in 2nd quad)

then sinŲ + 4cosŲ = 8/17 + 4(-15)/17 = -52/17

or

sinŲ = -8/17 (in 3rd quad)

then sinŲ + 4cosŲ = -8/17 + 4(-15/17) = -68/17

Case 2: cosŲ = 1

then sinŲ = 0

and sinŲ + 4cosŲ = 0 + 4(1) = 4

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