Find x, if sin x = cos (x – 20°)
WBBSE
Class X
Mathematics
Trigonometric Ratio of Complementary Angle
02 Mark
2025
cos (x – 20°) = sin x
cos (x – 20°) = cos (90° – x)
Since cos A = cos B implies A = B or A + B = 360°, we equate:
x – 20° = 90° – x
Solving:
x + x = 90° + 20°
2x = 110°
x = 55°
Thus, x = 55°.
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