AP EAMCET · Maths · Trigonometric Ratios & Identities
If \(\cos A=\frac{7}{25}\) and \(\frac{3 \pi}{2} < A < 2 \pi\), then \(\cos \frac{A}{4}+\cos \frac{A}{2}-\cos 2 A=\)
- A \(\frac{1}{\sqrt{10}}+\frac{27}{625}\)
- B \(\frac{3}{\sqrt{10}}-\frac{27}{625}\)
- C \(\frac{3}{\sqrt{10}}+\frac{27}{625}\)
- D \(\frac{1}{\sqrt{10}}-\frac{27}{625}\)
Answer & Solution
Correct Answer
(A) \(\frac{1}{\sqrt{10}}+\frac{27}{625}\)
Step-by-step Solution
Detailed explanation
Given, \(\quad \cos A=\frac{7}{25}\) and \(\frac{3 \pi}{2} < A < 2 \pi\) Then, \(\quad \cos 2 A=2\left(\frac{49}{625}\right)-1=\frac{98-625}{625}=-\frac{527}{625}\) \(\cos \frac{A}{2}=-\frac{4}{5}\) and \(\cos \frac{A}{4}=\frac{1}{\sqrt{10}}\) So,…
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Maths
- The parametric form of a curve is , thenAP EAMCET 2022 Hard
- The point on the line \(3 x+4 y=5\) which is equidistant from \((1,2)\) and \((3,4)\) isAP EAMCET 2009 Medium
- In a \(\triangle A B C\)
\[
\frac{(a+b+c)(b+c-a)(c+a-b)(a+b-c)}{4 b^2 c^2}
\]
equalsAP EAMCET 2009 Easy - If \(\frac{3+2 i \sin \theta}{1-2 i \sin \theta}\) is a real number and \(0 < \theta < 2 \pi\), then \(\theta\) is equal toAP EAMCET 2002 Easy
- Four cards are drawn at random from a pack of playing cards. The probability of getting exactly two cards from the same suit and the remaining two cards from two different suits isAP EAMCET 2018 Medium
- If \(\mathrm{c}\) and \(\mathrm{d}\) are arbitrary constants, then \(y=e^{2 x}(\cosh \sqrt{2} x+d \sinh \sqrt{2} x)\) is the general solution of the differential equationAP EAMCET 2023 Medium
More PYQs from AP EAMCET
- If the probability function of a random variable \(\mathrm{X}\) is given by \(P(X=j)=\frac{1}{2^j} ; j=1,2,3, \ldots, \infty\) then the variance ofAP EAMCET 2018 Medium
- The equation of the circle concentric with the circle \(x^2+y^2-6 x+12 y+15=0\) and of double its area isAP EAMCET 2010 Hard
- The work done by a force in displacing a body from to isAP EAMCET 2019 Easy
- A Zener diode voltage regulator operated in the range \(120 \mathrm{~V}-180 \mathrm{~V}\) produces a constant supply of \(110 \mathrm{~V}\) and \(250 \mathrm{~mA}\) to the load. If the maximum current is equally shared between the load and the Zener diode, then the values of load resistance \(\left(R_L\right)\) and series resistance \(\left(R_S\right)\) are respectivelyAP EAMCET 2017 Easy
- \(\int_{-\frac{\pi}{2}}^{\frac{\pi}{2}} \sin (x-[x]) d x=\)AP EAMCET 2025 Medium
- The oxidation state of phosphorus in cyclo-tri-meta phosphoric acid isAP EAMCET 2020 Medium