Question

If x = a sec θ and y = b tan θ, then b²x²− a²y² = 

A. ab 

B. a²− b² 

C. a² + b² 

D. a² b²

Answer 1

Given: x = a sec θ and y = b tan θ 

⇒ x² = a² sec² θ and y² = b² tan²θ ……(i) 

To find: b²x² – a²y² 

Consider b²x² – a²y² = b² a² sec²θ – a² b² tan²θ 

= a² b² (sec²θ – tan²θ) 

= a²b² (1) [∵ sec²θ – tan²θ = 1] 

= a²b²