Question

Prove : cosec 2 72- tan 2 18= 1

Answer 1

cosec2(90-18)- tan 2 (90-72)
2 sec18- tan18
by using the identity,
1 ans

Answer 2

Answer:cosec^2(72)-tan^2 (18)=1

Cosec^2 (90-18)-tan^2 (90-72)=1

Sec^2 (18)-tan^2 (18)=1

Hence,we know that [sec^2A-tan^2A=1],we get

Sec^2 (18)-tan^2 (18)=1

HENCE PROVED

Step-by-step explanation: