Question

Without using the trigonometric tables evaluate the following:
(Cos²25° + cos²65°)+cosec teta .sec(90°-teta)- cot teta tan(90°-teta)

Answer 1

use the concept of complementary angles and trigonometric identities.

Answer 2

Simple dear I will start without writing question plz If u want split it into three parts

Cos2 ( 90- 65) + cos2 65
= sin2 65 +cos2 65 ( sin2 teta
+cos2 teta =1)
=1

Cosec teta * cosec teta. ( sec(90- a)=
cosec a)
Cosec2 teta

Cot teta * cot teta ( tan(90-a) = cot a)
Cot 2 teta
Put it together
1+ cosec2 teta - cot2 teta
=1+1. ( cosec2 teta - cot2 teta =1)
= 2