Answer:
-1
Step-by-step explanation:
We need to find the value of tan² 70° -sec² 70°.
We know that,
[tex]\sec^2\theta-\tan^2\theta=1[/tex] ...(1)
We can write the given expression as :
tan² 70° -sec² 70° = -(-tan² 70° +sec² 70°)
=-(sec² 70°-tan² 70°)
Using identity (1)
=-(1)
= -1
Hence, the value of the given expression is -1.
