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If \(\vec{a}\)=\(\hat{i}\)+4\(\hat{j}\) and \(\vec{b}\)=3\(\hat{i}\)-3\(\hat{j}\). Find the magnitude of \(\vec{a}+\vec{b}\).(a) \(\sqrt{6}\)(b) \(\sqrt{11}\)(c) \(\sqrt{5}\)(d) \(\sqrt{17}\)I had been asked this question in homework.My question is from Addition of Vectors topic in portion Vector Algebra of Mathematics – Class 12

Answer»

The CORRECT choice is (d) \(\sqrt{17}\)

Explanation: Given that, \(\vec{a}\)=\(\hat{i}\)+4\(\hat{j}\) and \(\vec{B}\)=3\(\hat{i}\)-3\(\hat{j}\)

∴\(\vec{a}+\vec{b}\)=(1+3) \(\hat{i}\)+(4-3) \(\hat{j}\)

=4\(\hat{i}\)+\(\hat{j}\)

|\(\vec{a}+\vec{b}\)|=\(\sqrt{4^2+1^2}=\sqrt{16+1}=\sqrt{17}\)



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