Exercise 1

The value of \[\mathbf{sin}\text{ }(\mathbf{2}\text{ }\mathbf{ta}{{\mathbf{n}}^{-\mathbf{1}}}\left( \mathbf{0}.\mathbf{75} \right))\] is equal to (a) \[\mathbf{0}.\mathbf{75}\] (b) \[\mathbf{1}.\mathbf{5}\] (c) \[\mathbf{0}.\mathbf{96}\] (d) \[\mathbf{sin}\text{ }\mathbf{1}.\mathbf{5}\]

The correct option is  (c) \[\mathbf{0}.\mathbf{96}\] We have, \[sin\text{ }(2\text{ }ta{{n}^{-1}}\left( 0.75 \right))\]

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If \[\mathbf{cos}\text{ }(\mathbf{si}{{\mathbf{n}}^{-\mathbf{1}}}~\mathbf{2}/\mathbf{5}\text{ }+\text{ }\mathbf{co}{{\mathbf{s}}^{-\mathbf{1}}}~\mathbf{x})\text{ }=\text{ }\mathbf{0}\], then x is equal to (a) \[\mathbf{1}/\mathbf{5}\] (b) \[\mathbf{2}/\mathbf{5}\] (c) \[\mathbf{0}\] (d) \[1\]

The correct option is  (b) \[\mathbf{2}/\mathbf{5}\] Given, \[cos\text{ }(si{{n}^{-1}}~2/5\text{ }+\text{ }co{{s}^{-1}}~x)\text{ }=\text{ }0\] So, this can be rewritten as \[\begin{array}{*{35}{l}}...

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The domain of the function by f(x) = \[\mathbf{si}{{\mathbf{n}}^{-\mathbf{1}}}~\sqrt{\left( \mathbf{x}\text{ }\text{ }\mathbf{1} \right)}\] is (a) \[\left[ \mathbf{1},\text{ }\mathbf{2} \right]\] (b) \[\left[ -\mathbf{1},\text{ }\mathbf{1} \right]\] (c) \[\left[ \mathbf{0},\text{ }\mathbf{1} \right]\] (d) none of these

The correct option is  (a) \[\left[ \mathbf{1},\text{ }\mathbf{2} \right]\] We know that, \[si{{n}^{-1}}~x\] is defined for \[x\in \left[ -1,\text{ }1 \right]\] So, f(x) =...

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The domain of the function \[\mathbf{cos}-\mathbf{1}\text{ }\left( \mathbf{2x}-\text{ }\text{ }\mathbf{1} \right)\]is (a) \[\left[ \mathbf{0},\text{ }\mathbf{1} \right]\] (b) \[\left[ -\mathbf{1},\text{ }\mathbf{1} \right]\] (c) \[\left[ -\mathbf{1},\text{ }\mathbf{1} \right]\] (d) \[\left[ \mathbf{0},\text{ }\mathbf{\pi } \right]\]

The correct option is  (a) \[\left[ \mathbf{0},\text{ }\mathbf{1} \right]\] Since, \[cos-1\text{ }x\] is defined for \[x\in \left[ -1,\text{ }1 \right]\] So, f(x) = \[\mathbf{cos}-\mathbf{1}\text{...

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If \[\mathbf{3}\text{ }\mathbf{ta}{{\mathbf{n}}^{-\mathbf{1}}}~\mathbf{x}\text{ }+\text{ }\mathbf{co}{{\mathbf{t}}^{-\mathbf{1}}}~\mathbf{x}\text{ }=\text{ }\mathbf{\pi }\], then x equals (a) \[\mathbf{0}\] (b) \[\mathbf{1}\] (c) \[-\mathbf{1}\] (d) ½

The correct option is  (b) \[\mathbf{1}\] Given, \[\mathbf{3}\text{ }\mathbf{ta}{{\mathbf{n}}^{-\mathbf{1}}}~\mathbf{x}\text{ }+\text{ }\mathbf{co}{{\mathbf{t}}^{-\mathbf{1}}}~\mathbf{x}\text{...

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Which of the following is the principal value branch of \[\mathbf{cose}{{\mathbf{c}}^{-\mathbf{1}}}~\mathbf{x}\]? (a) \[\left( -\mathbf{\pi }/\mathbf{2},\text{ }\mathbf{\pi }/\mathbf{2} \right)\] (b) \[\left[ \mathbf{0},\text{ }\mathbf{\pi } \right]\text{ }\text{ }\left\{ \mathbf{\pi }/\mathbf{2} \right\}\] (c) \[\left[ -\mathbf{\pi }/\mathbf{2},\text{ }\mathbf{\pi }/\mathbf{2} \right]\] (d) \[\left[ -\mathbf{\pi }/\mathbf{2},\text{ }\mathbf{\pi }/\mathbf{2} \right]\text{ }\text{ }\left\{ \mathbf{0} \right\}\]

The correct option is (d) \[\left[ -\mathbf{\pi }/\mathbf{2},\text{ }\mathbf{\pi }/\mathbf{2} \right]\text{ }\text{ }\left\{ \mathbf{0} \right\}\] According to the principal branch of...

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Which of the following is the principal value branch of \[\mathbf{cos}-\mathbf{1}\text{ }\mathbf{x}\]? (a) \[\left[ -\mathbf{\pi }/\mathbf{2},\text{ }\mathbf{\pi }/\mathbf{2} \right]\] (b) \[\left( \mathbf{0},\text{ }\mathbf{\pi } \right)\] (c) \[\left[ \mathbf{0}.\text{ }\mathbf{\pi } \right]\] (d) \[\left[ \mathbf{0},\text{ }\mathbf{\pi } \right]\text{ }\text{ }\left\{ \mathbf{\pi }/\mathbf{2} \right\}\]

The correct answer is (c) \[\left[ \mathbf{0}.\text{ }\mathbf{\pi } \right]\] According to the principal value branch \[co{{s}^{-1}}~x\] is \[\left[ 0,\text{ }\pi  \right]\].

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If \[{{\mathbf{a}}_{\mathbf{1}}},\text{ }{{\mathbf{a}}_{\mathbf{2}}},\text{ }{{\mathbf{a}}_{\mathbf{3}}},\text{ }\ldots .,\text{ }{{\mathbf{a}}_{\mathbf{n}}}~\] is an arithmetic progression with common difference d, then evaluate the following expression.

Given \[{{\mathbf{a}}_{\mathbf{1}}},\text{ }{{\mathbf{a}}_{\mathbf{2}}},\text{ }{{\mathbf{a}}_{\mathbf{3}}},\text{ }\ldots .,\text{ }{{\mathbf{a}}_{\mathbf{n}}}~\] is an arithmetic progression with...

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Show that \[\mathbf{ta}{{\mathbf{n}}^{-\mathbf{1}}}~(\mathbf{1}/\mathbf{2}\text{ }\mathbf{si}{{\mathbf{n}}^{-\mathbf{1}}}~\mathbf{3}/\mathbf{4})\text{ }=\text{ }\left( \mathbf{4}\text{ }\text{ }\surd \mathbf{7} \right)/\text{ }\mathbf{3}\] and justify why the other value \[\left( \mathbf{4}\text{ }+\text{ }\surd \mathbf{7} \right)/\text{ }\mathbf{3}\]is ignored.

We have, \[ta{{n}^{-1}}\left( 1/2\text{ }si{{n}^{-1}}~3/4 \right)\] Let, \[~{\scriptscriptstyle 1\!/\!{ }_2}\text{ }si{{n}^{-1}}~{\scriptscriptstyle 3\!/\!{ }_4}\text{ }=\text{ }\theta \] or,...

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Show that \[\mathbf{si}{{\mathbf{n}}^{-\mathbf{1}}}~\mathbf{5}/\mathbf{13}\text{ }+\text{ }\mathbf{co}{{\mathbf{s}}^{-\mathbf{1}}}~\mathbf{3}/\mathbf{5}\text{ }=\text{ }\mathbf{ta}{{\mathbf{n}}^{-\mathbf{1}}}~\mathbf{63}/\mathbf{16}\text{ }\]

Solution: Here, \[si{{n}^{-1}}~5/13\text{ }=\text{ }ta{{n}^{-1}}~5/12\] And, \[co{{s}^{-1}}~3/5\text{ }=\text{ }ta{{n}^{-1}}~4/3\] Taking the L.H.S, we have Thus, L.H.S = R.H.S – Hence Proved...

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Prove that \[\mathbf{si}{{\mathbf{n}}^{-\mathbf{1}}}~\mathbf{8}/\mathbf{17}\text{ }+\text{ }\mathbf{si}{{\mathbf{n}}^{-\mathbf{1}}}~\mathbf{3}/\mathbf{5}\text{ }=\text{ }\mathbf{si}{{\mathbf{n}}^{-\mathbf{1}}}~\mathbf{77}/\mathbf{85}\]

Taking the L.H.S, = \[\mathbf{si}{{\mathbf{n}}^{-\mathbf{1}}}~\mathbf{8}/\mathbf{17}\text{ }+\text{ }\mathbf{si}{{\mathbf{n}}^{-\mathbf{1}}}~\mathbf{3}/\mathbf{5}\] = tan-1 8/15 + tan-1 3/4 – Hence...

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. Find the simplified form of \[\mathbf{co}{{\mathbf{s}}^{-\mathbf{1}}}~\left[ \mathbf{3}/\mathbf{5}\text{ }\mathbf{cos}\text{ }\mathbf{x}\text{ }+\text{ }\mathbf{4}/\mathbf{5}\text{ }\mathbf{sin}\text{ }\mathbf{x} \right],\text{ }\mathbf{x}\in \left[ -\mathbf{3\pi }/\mathbf{4},\text{ }\mathbf{\pi }/\mathbf{4} \right]\].

We have, \[\mathbf{co}{{\mathbf{s}}^{-\mathbf{1}}}~\left[ \mathbf{3}/\mathbf{5}\text{ }\mathbf{cos}\text{ }\mathbf{x}\text{ }+\text{ }\mathbf{4}/\mathbf{5}\text{ }\mathbf{sin}\text{ }\mathbf{x}...

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If \[\mathbf{2}\text{ }\mathbf{ta}{{\mathbf{n}}^{-\mathbf{1}}}\left( \mathbf{cos}\text{ }\mathbf{\theta } \right)\text{ }=\text{ }\mathbf{ta}{{\mathbf{n}}^{-\mathbf{1}}}~\left( \mathbf{2}\text{ }\mathbf{cosec}\text{ }\mathbf{\theta } \right)\],then show that \[\mathbf{\theta }\text{ }=\text{ }\mathbf{\pi }/\mathbf{4}\].

Given, \[\mathbf{2}\text{ }\mathbf{ta}{{\mathbf{n}}^{-\mathbf{1}}}\left( \mathbf{cos}\text{ }\mathbf{\theta } \right)\text{ }=\text{ }\mathbf{ta}{{\mathbf{n}}^{-\mathbf{1}}}~\left( \mathbf{2}\text{...

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Show that \[\mathbf{2}\text{ }\mathbf{ta}{{\mathbf{n}}^{-\mathbf{1}}}\left( -\mathbf{3} \right)\text{ }=\text{ }\text{ }\mathbf{\pi }/\mathbf{2}\text{ }+\text{ }\mathbf{ta}{{\mathbf{n}}^{-\mathbf{1}}}\left( -\mathbf{4}/\mathbf{3} \right)\]

Taking L.H.S = \[2\text{ }ta{{n}^{-1}}\left( -3 \right)\text{ }=\text{ }-2\text{ }ta{{n}^{-1}}~3\text{ }(\because ta{{n}^{-1}}~\left( -x \right)\text{ }=\text{ }\text{ }ta{{n}^{-1}}~x)\text{ }\in...

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Find the value of \[\mathbf{ta}{{\mathbf{n}}^{-\mathbf{1}}}~\left( -\mathbf{1}/\surd \mathbf{3} \right)\text{ }+\text{ }\mathbf{co}{{\mathbf{t}}^{-\mathbf{1}}}\left( \mathbf{1}/\surd \mathbf{3} \right)\text{ }+\text{ }\mathbf{ta}{{\mathbf{n}}^{-\mathbf{1}}}\left( \mathbf{sin}\text{ }\left( -\mathbf{\pi }/\mathbf{2} \right) \right)\]

According to the question, \[\mathbf{ta}{{\mathbf{n}}^{-\mathbf{1}}}~\left( -\mathbf{1}/\surd \mathbf{3} \right)\text{ }+\text{ }\mathbf{co}{{\mathbf{t}}^{-\mathbf{1}}}\left( \mathbf{1}/\surd...

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Find the value of \[\mathbf{ta}{{\mathbf{n}}^{-\mathbf{1}}}~\left[ \mathbf{tan}\text{ }\left( \mathbf{5\pi }/\mathbf{6} \right) \right]\text{ }+\text{ }\mathbf{co}{{\mathbf{s}}^{-\mathbf{1}}}~\left[ \mathbf{cos}\text{ }\left( \mathbf{13\pi }/\mathbf{6} \right) \right]\]

We know that, \[ta{{n}^{-1}}~tan\text{ }x\text{ }=\text{ }x,\text{ }x\in \left( -\pi /2,\text{ }\pi /2 \right)\] And, here \[ta{{n}^{-1}}~tan\text{ }\left( 5\pi /6 \right)\text{ }=\text{ }5\pi...

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