Question

Use a double angle formula to find the exact value of cos 117

Answer 1

Comen we know Cushi ) = + 3 .. we know Cos (1 x ) = F So. Cosao = 2 los²0-1 & Cosro I - 2x 11 Coso = so Gas (140) = + | 14 (exabit) = + /14574 2 het in in second quadrant so cus sünegotian Ces in - Vitis ang 10.5 a=80 in A=250, 6=12, C=20 2gncen < 6=20 " a² b ² + c = a be as of so a² = 144+ you-241 2420 Cosas = 144 +400-48044 0.90) a2= 6 8 110.2 Ta = 10.3 New SinB = sinA & Sin B= b sinA = 162 x Sinzs ( 12 42- ) 124 0.42 0.48 &9B- Sint (0.48) C Scanned with CamScanner RO

Sinca fina 7 since Sma=20_Sinz5= 200.42) = 0.8 10 IC- Si-(6-8) A = 30, B = 100, c= 25 (c = 180-LB-LA Lc = 50° A 25 B SIMB 25x - 8 din 10 Sinsol 0.77 sinc 76= c. sing. 28Sim 10 = 25X0:44 Tb = 31-8) Sina a = c.Sim - 0.77 A = 250 Sin 30 = 2500.5=16.2 Singo sme a = 16.2 Niz A 4 3 | given tant of So sint= B = 1 Cost = A = 7 cott AB = 4 seet = AE = Jiz Inned with Esschien AC = 117 AC А С inner