Question
Mathematics Question on Properties of Inverse Trigonometric Functions
The value of cos(2cos−1x+sin−1x) at x=51 is
A
−526
B
−26
C
−56
D
None
Answer
−526
Explanation
Solution
cos(2cos−1x+sin−1x) =cos(cos−1x+cos−1x+sin−1x) =cos(cos−1x+π/2)=−sincos−1x =−sinsin−11−x2=−1−x2 =−1−(51)2=−2524=−526