1.

If sinA=(3)/(5)"where "450^(@)ltAlt540^(@),then "cos"(A)/(2) is equal to

Answer»

`(1)/(sqrt(10))`
`-sqrt((3)/(10))`
`(sqrt(3))/(sqrt(10))`
None of the above

Solution :`sinA=(3)/(5),450^(@)ltAlt54^(@)`
`rArr225^(@)lt(A)/(2)lt270^(@)`
`COSA=(-4)/(5)(because A" LIES in Q 2")`

`therefore"cos"^(2)(A)/(2)=(1+cosA)/(2)=(1)/(10)`
`RARR"cos"(A)/(2)=(-1)/(sqrt(10))(because(A)/(2)" lies in Q 3")`


Discussion

No Comment Found

Related InterviewSolutions