Flag Trigonometry> If tan^2B=sin^2A-cos^2A then prove that t...
question mark

If tan^2B=sin^2A-cos^2A then prove that tan^2A=sin^2B-cos^B

Preeti rani sah , 5 Years ago
Grade 11
anser 1 Answers
Harshit Singh
Dear Student

you did mistake in typing question ,it should be like this
cos²A - sin²A = tan²B , then prove , cos²B - sin²B = tan²A

Given, cos²A - sin²A = tan²B
⇒cos²A - ( 1 - cos²A ) = tan²B [∵ sin²Ф = 1 - cos²Ф ]
⇒ cos²A - 1 + cos²A = tan²B
⇒ 2cos²A - 1 = tan²B
⇒ 2cos²A = 1 + tan²B
⇒ 2cos²A = sec²B [ ∵ sec²Ф = 1 + tan²Ф ]
⇒2cos²A.cos²B =1 [ ∵ secФ = 1/cosФ ]
⇒2cos²B = sec²A
= cos²B + cos²B = 1 + tan²A
⇒ cos²B + cos²B - 1 = tan²A
⇒cos²B - (1 - cos²B) = tan²A
⇒ cos²B - sin²B = tan²A
Hence proved

Thanks
Last Activity: 5 Years ago
star
LIVE ONLINE CLASSES

Prepraring for the competition made easy just by live online class.

tv

Full Live Access

material

Study Material

removal

Live Doubts Solving

assignment

Daily Class Assignments