Question

Find the exact value of the expression cos(sin If sin = sin 2 15 find the exact value of cos(20)

Answer 1

solution: To Given the expression - cos(sin's 2 Noia) 13 we find the exact volwe of this expressien. ) = cos(casting l: use formula Cos (sint 2- (sin'x = cost / x2) 14-3 1 cos ( Soni! 15 ) Ans 2 2 2 If Sino = 2 then find Gas (20) is Now, we used the identidy (0320 = 1-2 fin? =128) Sino= 1 S 5-0 5 Cos 20 = -3 Ans 5 I sclue Sinaa= wszu where 0217 NOW, Dividing borth siches by C0723, Sin2x CS2 x } fan Ty sof fanaa dano = tana. fana, then

© 2x = km + Ty where kro,1,2,3---- put ko, in equation © 2x = ot / To x = put ka in equation o 22 TT + TT UTAT 4 27 = S T 4 571 25 put k = 2 in nation o T/ 2 1 = = 2 7 11 = 97! U 911 8 Pul k=3 in equation o 2x = 311 + Ty 2x = 13T y N = 137 Hence, X = IT ST GT 13T o 137) Aus 1 The value of x Sement belonging to the interval is olacat