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The acute angle which the perpendicular from the origin on the line 7x –3y = 4 makes with the x-axis is:(a) zero (b) positive but not \(\frac{\pi}{4}\)(c) negative (d) \(\frac{\pi}{4}\) |
Answer» (c) negative As the line from the origin is perpendicular to the line 7x – 3y = 4, so its slope = \(\frac{-1}{\text{slope of }\,7x-3y=4}\) Slope of 7x – 3y – 4 = \(\frac{7}{3}\) ∴ Slope of line from origin = \(\frac{-1}{+\frac{7}{3}}\) = \(\frac{-3}{7}\) ∴ tan θ = \(\frac{-3}{7}\), where θ is the angle the line makes with the +ve direction of x-axis ⇒ θ = tan-1 \(\big(\frac{-3}{7}\big)\) = - tan-1 \(\big(\frac{3}{7}\big)\) |
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