Question

If Cosx=-1/3 and x lies in third quadrant find the values of sinx/2,cosx/2and tanx/2. ​

Answer 1

Cos x= -1÷3

according to Pythagoras

AC sq= AB sq+BC sq

(3)sq= (-1)sq + BC sq

9= 1+ BC sq

BC = √8

sinx= √8÷3

cos x= -1÷3

tanx √8 ÷-1

Answer 2

cos x=-1/3

we have base and hypo so we have to find perpedicular

let a be -1

let b be 3

(c)2=(a)2-(b)2

(c)2=(-1)2-(3)2

(c)2=1-9

c=4

sinx/2=4/3/2

sinx/2=7/3 answer

cosx/2=-1/3/2

cosx/2=-2/3 answer

tanx/2=4/-1/2

tanx/2=-8 answer