Q14Long answer
If θ1, θ2, θ3, ..., θn are in A.P., whose common difference is d, show that tan θn − tan θ1 secθ1 secθ2 + secθ2 secθ3 + ... + secθn–1 secθn = . sin d
If θ1, θ2, θ3, ..., θn are in A.P., whose common difference is d, show that tan θn − tan θ1 secθ1 secθ2 + secθ2 secθ3 + ... + secθn–1 secθn = . sin d