Question

If `cos A=4/5`, then the value of `tanA` is
A. `3/5`
B. `3/4`
C. `4/3`
D. `5/3`

Answer 1

Correct Answer - B
Given, cosA=`4/5`
`therefore sinA = sqrt(1-cos^(2)A)` `[therefore sin^(2)A+ cos^(2)A=1]` `[therefore sinA=sqrt(1-cos^(2)A)]`
`=sqrt(1-(4/5)^(2))=sqrt(1-(16/25))=sqrt(9/25)=3/5`
Now, `tanA=(sinA)/(cosA) = (3/5)/(4/5)=3/4`
Hence, the required value of tan A is `3/4`