English: Because Cosθ_(Z) is 0, θ_(Z) that being π / 2 and from here you can get Cos ω at sunrise which is Cos inverse of – Tan δ Tanϕ.
Telugu: ఎందుకంటే Cosθ_(Z)=0,అంటే θ_(Z)= π / 2 దీని నుండి మీరు Cos ω పొందవచ్చు.