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AP EAMCET · Maths · Three Dimensional Geometry

If a line makes angles \(\frac{\pi}{4}\) and \(\frac{\pi}{3}\) with \(Y\)-axis and \(Z\)-axis respectively, then the obtuse angle made by that line with \(X\)-axis is

  1. A \(\frac{\pi}{3}\)
  2. B \(\frac{2 \pi}{3}\)
  3. C \(\frac{\pi}{6}\)
  4. D \(\frac{5 \pi}{6}\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(\frac{2 \pi}{3}\)

Step-by-step Solution

Detailed explanation

Let line makes angle \(\alpha\) with \(X\)-axis then, direction cosine of the line are \[ l=\cos \alpha, m=\cos \frac{\pi}{4}, n=\cos \frac{\pi}{3} \] But \[ l^2+m^2+n^2=1 \]…