Q12 of 118 Page 5

Mark the correct alternative in the following:

If , then cos x is equal to


Given:


Let cosec x =a, cot x = b


∴ According to the question


⇒


But, cosec2x –cot2x =1


⇒ a2 – b2 = 1


⇒ (a-b) (a + b) = 1



⇒ a + b=2


a-b =1/2 …(1)


a + b =2 …(2)


Adding (1) and (2)


2a = 1/2+2


⇒ a = 5/4




Cos2x = 1 – sin2x




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