The angle between the lines \(x \cos 85^{\circ}+y \sin 85^{\circ}=1\) and \(x \cos 40^{\circ}+y \sin 40^{\circ}=2\) is : (a) \(90^{\circ}\) (b) \(80^{\circ}\) (c) \(125^{\circ}\) (d) \(45^{\circ}\)

Short Answer

Expert verified
The angle between the lines is (b) \(80^{\circ}\).

Step by step solution

01

Find Direction Ratios of Line 1

Let \(A_1(x_1, y_1)\) be a point on Line 1 such that \(x_1 \cos 85^{\circ} + y_1 \sin 85^{\circ} = 1\). We can find the direction ratios of Line 1 by considering the vector \(\vec{A_1}\).
02

Find Direction Ratios of Line 2

Let \(A_2(x_2, y_2)\) be a point on Line 2 such that \(x_2 \cos 40^{\circ} + y_2 \sin 40^{\circ} = 2\). Similarly, we can find the direction ratios of Line 2 by considering the vector \(\vec{A_2}\).
03

Calculate the Dot Product and Angle between Direction Ratios

Now that we have the direction of vectors for both lines, we can find the angle between them. Let \(\vec{v_1}\) and \(\vec{v_2}\) be the direction vectors for Line 1 and Line 2 respectively. The angle between these two lines, \(\theta\), can be found using the dot product formula: \[\cos \theta = \frac{\vec{v_1} \cdot \vec{v_2}}{||\vec{v_1}|| \; ||\vec{v_2}||}\] Where \(\vec{v_1} \cdot \vec{v_2}\) is the dot product of the direction vectors and ||\(\vec{v_1}\)|| and ||\(\vec{v_2}\)|| are the magnitudes of the direction vectors.
04

Calculate the Values and Choose the Correct Answer

After finding the value of the angle \(\theta\), we can compare it to the given options and choose the one that matches. (a) \(90^{\circ}\) (b) \(80^{\circ}\) (c) \(125^{\circ}\) (d) \(45^{\circ}\)

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Study anywhere. Anytime. Across all devices.

Sign-up for free