Why Does the Pendulum Angle Calculation Show 60° Instead of 30°?

[cupid.callin]

Homework Statement

The Attempt at a Solution

Here my figure showing forces:

SO here,

Tcosθ = mg
Tsinθ = ma_o

so tanθ =a_o/g = 1/√3

so θ = 30^o, right?

but it answer says its 60^o

 

[vipulgoyal]

books wrong... i also got the same asnwer

 

[cupid.callin]

that can't be
book hasn't been wrong ever till now (and i have done like 80% of it)

 

[cupid.callin]

Does everyone think that answer is 30 ?