Question

find the value of sec²42° - cosec²48°

Answer 1

sec^2(90-48)- cosec ^2 48

= cosec ^2 48 - cosec ^2 48

= 0
since sec(90-θ)=cosec θ

Answer 2

• sec² 42° - cosec² 48°
• sec² (90° - 48°) - cosec² 48°
• cosec² 48° - cosec² 48°
• by using $\bold\red{sec(90-A)\:=\:cosecA) }$
• by squaring both sides we get
• sec²(90 - A) = cosec²A
• 0