Find the maximum and minimum values...
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Find the maximum and minimum values of following trigonometric functions E-2. Find the cos 2x + cos2x (ii) cosa (+ x + (sinx – cos x)2

JEE/Engineering Exams
Maths
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D cos ( 2 x=2 cos ^{2} x-1 ) " ( cos u x+cos ^{2} x=3 cos ^{2} x-1 ) ( 0 leq cos ^{2} x leq 1 ) ( 0 leq 3 cos ^{2} x leq 3 ) ( -1 leq 3 cos ^{2} x-1 leq 2 ) ( - ) ( therefore cos 2 x+cos ^{2} x inleft[begin{array}{cc}-1 & 2end{array}right] ) 11) ( quadleft[cos left(x+frac{pi}{4}right)right]^{2}=left(frac{cos x}{sqrt{2}}-frac{sin x}{sqrt{2}}right)^{2} ) ( begin{aligned} &=frac{(cos x-sin x)^{2}}{2} therefore quad cos ^{2}(pi / u+x)+(sin x-cos x)^{2} =& frac{3}{2}(cos x-sin x)^{2} therefore &(cos x-sin x)^{2} in[0,2] therefore & frac{3}{2}[cos x-sin x)^{2} in[0,3] end{aligned} )
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