\( a = -4 i + 2 j\), \( b..." - Step-by-step solution, answer key, and detailed explanation on MCA Prep.">
\(... - Solved | MCA Prep" />
\( a = -4 i + 2 j\), \( b..." - Step-by-step solution, answer key, and detailed explanation on MCA Prep." />
\(... - Solved | MCA Prep" />
\( a = -4 i + 2 j\), \( b..." - Step-by-step solution, answer key, and detailed explanation on MCA Prep." />
For the vectors <span class="math-tex">\(\rm \vec a = -4\hat i + 2\hat j\)</span>, <span class="math-tex">\(\rm \vec b =2\hat i + \hat j\)</span> and <span class="math-tex">\(\rm \vec c = 2\hat i + 3\hat j\)</span>, if <span class="math-tex">\(\rm \vec c = m\vec a + n\vec b\)</span>, then the value of m + n is: Step-by-step Solution: To find the values of \( m \) and \( n \) such that \( \vec{c} = m\vec{a} + n\vec{b} \), we can proceed with the following steps:
1. Given Vectors:
\[
\vec{a} = -4\hat{i} + 2\hat{j}
\]
\[
\vec{b} = 2\hat{i} + \hat{j}
\]
\[
\vec{c} = 2\hat{i} + 3\hat{j}
\]
2. Express \( \vec{c} \) in Terms of \( \vec{a} \) and \( \vec{b} \):
\[
\vec{c} = m\vec{a} + n\vec{b}
\]
Substitute the given vectors:
\[
2\hat{i} + 3\hat{j} = m(-4\hat{i} + 2\hat{j}) + n(2\hat{i} + \hat{j})
\]
\[
2\hat{i} + 3\hat{j} = (-4m + 2n)\hat{i} + (2m + n)\hat{j}
\]
3. Set Up Equations by Comparing Components:
- For \( \hat{i} \) components:
\[
-4m + 2n = 2
\]
- For \( \hat{j} \) components:
\[
2m + n = 3
\]
4. Solve the System of Equations:
From the second equation:
\[
n = 3 - 2m
\]
Substitute \( n = 3 - 2m \) into the first equation:
\[
-4m + 2(3 - 2m) = 2
\]
\[
-4m + 6 - 4m = 2
\]
\[
-8m + 6 = 2
\]
\[
-8m = -4
\]
\[
m = \frac{1}{2}
\]
Substitute \( m = \frac{1}{2} \) back into \( n = 3 - 2m \):
\[
n = 3 - 2\left(\frac{1}{2}\right) = 3 - 1 = 2
\]
5. Find \( m + n \):
\[
m + n = \frac{1}{2} + 2 = \frac{5}{2}
\]
Therefore, the value of \( m + n \) is:
\[
\boxed{\frac{5}{2}}
\]Question 7
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