Question 1:
Find the value of
ANSWER:
We know that cos−1 (cos x) = x if, which is the principal value branch of cos −1x.
Here,
Now, can be written as:
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Question 2:
Find the value of
ANSWER:
We know that tan−1 (tan x) = x if, which is the principal value branch of tan −1x.
Here,
Now, can be written as:
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Question 3:
Prove
ANSWER:
Now, we have:
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Question 4:
Prove
ANSWER:
Now, we have:
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Question 5:
Prove
ANSWER:
Now, we will prove that:
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Question 6:
Prove
ANSWER:
Now, we have:
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Question 7:
Prove
ANSWER:
Using (1) and (2), we have
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Question 8:
Prove
ANSWER:
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Question 9:
Prove
ANSWER:
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Question 10:
Prove
ANSWER:
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Question 11:
Prove [Hint: putx = cos 2θ]
ANSWER:
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Question 12:
Prove
ANSWER:
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Question 13:
Solve
ANSWER:
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Question 14:
Solve
ANSWER:
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Question 15:
Solveis equal to
(A) (B) (C) (D)
ANSWER:
Let tan−1 x = y. Then,
The correct answer is D.
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Question 16:
Solve, then x is equal to
(A) (B) (C) 0 (D)
ANSWER:
Therefore, from equation (1), we have
Put x = sin y. Then, we have:
But, when, it can be observed that:
is not the solution of the given equation.
Thus, x = 0.
Hence, the correct answer is C.
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Question 17:
Solveis equal to
(A) (B). (C) (D)
ANSWER:
Hence, the correct answer is C.