JEE MATHEMATICS MCQ: SEQUENCE OF SERIES

1 Easy

1 of 1

Application +4 | -1

\cos (x-y), \cos x

and

\cos (x+y)

are in HP, the

\cos x \sec \left(\frac{y}{2}\right)

is equal to

View answer and explanation

Correct option: A

\pm \sqrt{2}

Option A (

\frac{1}{2}

) is correct because the ratio of the first term to the common difference is

\frac{1}{2}

, derived from the given condition that the sum of the first ten terms is four times the sum of the first five terms.

More Questions from SEQUENCE OF SERIES

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A=\{1,2,3\}, B=\{3,4\}, C=\{4,5,6\}

{A} \cup({B} \cap {C})

A-(B \cap C)

(B \cup C)-A

a,b,c

a,x,b

b,y,c

{x^2},{b^2},{y^2}

P(x)=1-x+x^2-x^3+\ldots+x^{2012}

y

Q(y)=a_0+a_1 y+\ldots+a_{2012} y^{2012}

y=x-2

\sum\limits_{{i=0}}^{2012} a_i

\log \left(\frac{5 c}{a}\right), \log \left(\frac{3 b}{5 c}\right)

\log \left(\frac{a}{3 b}\right)

A P

a, b

G P

a, b, c

\frac{3}{4}