MHT CET · Maths · Trigonometric Equations
If \(\sin x+\sin ^{2} x=1\), then \(\cos ^{8} x+2 \cos ^{6} x+\cos ^{4} x\) is
- A 3
- B 2
- C 1
- D 4
Answer & Solution
Correct Answer
(C) 1
Step-by-step Solution
Detailed explanation
Given \(\sin x+\sin ^{2} x=1 \Rightarrow \sin x=1-\sin ^{2} x\)
\(\begin{aligned} \therefore \sin x=\cos ^{2} x \Rightarrow \sin ^{2} x &=\cos ^{4} x \\ \cos ^{8} x+2 \cos ^{6} x+\cos ^{4} x &=\left(\cos ^{4} x+\cos ^{2} x\right)^{2} \\ &=\left(\sin ^{2} x+\cos ^{2} x\right)^{2}=1 \end{aligned}\)
\(\begin{aligned} \therefore \sin x=\cos ^{2} x \Rightarrow \sin ^{2} x &=\cos ^{4} x \\ \cos ^{8} x+2 \cos ^{6} x+\cos ^{4} x &=\left(\cos ^{4} x+\cos ^{2} x\right)^{2} \\ &=\left(\sin ^{2} x+\cos ^{2} x\right)^{2}=1 \end{aligned}\)
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
- If the normal to the curve \(y=f(x)\) at the point \((3,4)\) makes and angle \(\left(\frac{3 \pi}{4}\right)^{\mathrm{C}}\) with positive \(\mathrm{X}\)-axis, then \(f^{\prime}(3)\) is equal toMHT CET 2022 Medium
- If \(\overline{\mathrm{a}}, \overline{\mathrm{b}}, \overline{\mathrm{c}}\) are non-coplanar vectors and \(\overline{\mathrm{p}}=\frac{\overline{\mathrm{b}} \times \overline{\mathrm{c}}}{[\overline{\mathrm{a}} \overline{\mathrm{b}} \overline{\mathrm{c}}]}, \overline{\mathrm{q}}=\frac{\overline{\mathrm{c}} \times \overline{\mathrm{a}}}{[\overline{\mathrm{a}} \overline{\mathrm{b}} \overline{\mathrm{c}}]}, \overline{\mathrm{r}}=\frac{\overline{\mathrm{a}} \times \overline{\mathrm{b}}}{[\overline{\mathrm{a}} \overline{\mathrm{b}} \overline{\mathrm{c}}]}, \quad\) then \(2 \overline{\mathrm{a}} \cdot \overline{\mathrm{p}}+\overline{\mathrm{b}} \cdot \overline{\mathrm{q}}+\overline{\mathrm{c}} \cdot \overline{\mathrm{r}}=\)MHT CET 2024 Easy
- If \(\bar{a}+2 \bar{b}+3 \bar{c}=\overline{0}\) and \((\bar{b} \times \bar{b})+(\bar{b} \times \bar{c})+(\bar{c} \times \bar{a})=\lambda(\bar{b} \times \bar{c})\), then \(\lambda\) has the valueMHT CET 2022 Easy
- In a triangle \(A B C\), with usual notations, if \(a=5, b=4, \cos (A-B)=\frac{31}{32}\), then \(c=\)MHT CET 2025 Medium
- If the variance of the numbers \(2,3,11\) and \(x\) is \(\frac{49}{4}\), then the values of \(x\) areMHT CET 2021 Easy
- If the slope of the tangent of the curve at any point is equal to \(-y+\mathrm{e}^{-x}\), then the equation of the curve passing through origin isMHT CET 2023 Medium
More PYQs from MHT CET
- In an adiabatic process for an ideal gas, the relation between the universal gas constant ' \(R\) ' and specific heat at constant volume ' \(\mathrm{C}_{\mathrm{v}}\) ' is \(R=0 \cdot 4 C_v\). The pressure ' \(P\) ' of the gas is proportional to the temperature ' T ', of the gas as \(\mathrm{T}^k\). The value of constant ' K ' isMHT CET 2024 Hard
- A vertical spring oscillates with period 6 second with mass \(m\) is suspended from it. When the mass is at rest, the spring is stretched through a distance of
(Take, acceleration due to gravity, \(\mathrm{g}=\pi^2=10 \mathrm{~m} / \mathrm{s}^2\) )MHT CET 2025 Medium - Which one of the following is NOT the main postulate of Darwinism?MHT CET 2023 Medium
- A parallel combination of three condensers of capacities ' \(2 \mathrm{C}\), ' \(\mathrm{C}\) ' and ' \(\mathrm{C} / 2\) ' is connected
Across \(10 \mathrm{~V}\) battery. All the condensers are fully charged to charges ' \(\mathrm{Q}_1\) ', ' \(\mathrm{Q}_2\) ' and ' \(\mathrm{Q}\) 3' respectively. The ratio \(\mathrm{Q}_1: \mathrm{Q}_2: \mathrm{Q}_3\) isMHT CET 2022 Medium - Match hormones given in Column I with their source gland in Column II.
Choose the correct option from belowColumn I Column II i Oxytocin a. Adrenal medulla ii Melatonin b. Thyroid gland iii Catecholamines c. Pineal gland Iv Calcitonin d. Hypothalamus MHT CET 2024 Hard - A single slit diffraction pattern is formed with light of wavelength \(6195 Å\). The second secondary maximum for this wavelength coincides with the third secondary maximum in the pattern for light of wavelength ' \(\lambda_0\) '. The value of ' \(\lambda_0\) ' isMHT CET 2024 Easy