解:\tan\theta =3,则\cos 2\theta =\frac{\cos^2\theta -\sin^2\theta}{\cos^2\theta +\sin^2\theta }=\frac{1-tan^2\theta}{1+tan^2\theta } =\frac{1-9}{1+9} =-\frac{4}{5},所以C选项是正确的. 由条件利用角三角函数的基本关系,二倍角的余弦公式,求得\cos 2\theta 的值....
Step by step video, text & image solution for If the tangent at the point (2sec theta,3tan theta) to the hyperbola (x^(2))/(4)-(y^(2))/(9)=1 is parallel to 3x-4y+4=0, then the value of theta, is by Maths experts to help you in doubts & scoring excellent marks in Cla...
Doubtnut is the perfect NEET and IIT JEE preparation App. Get solutions for NEET and IIT JEE previous years papers, along with chapter wise NEET MCQ solutions. Get all the study material in Hindi medium and English medium for IIT JEE and NEET preparation ...
若tan0=3 ,则 sin20= ___. 答案 [答案] 35 结果二 题目 4.若$$ \tan \theta = 3 $$,则sin2θ=___. 答案 【答案】$$ \frac { 3 } { 5 } $$ 【解析】 由正弦函数的倍角公式和三角函数的基本关系式, 得$$ \sin 2 \theta = 2 \sin \theta \cos \theta = \frac {...
\displaystyle 1+tan^{2}A=sec^{2}A \displaystyle 1+cot^{2}A=csc^{2}A How to Understand?(如何理解?) ↓↓↓ 下面给出正六边形帮助大家去理解三角函数之间的关系: 图3 三角函数6变形法则(来源:Baidu) 其图形特征为——上弦中切下为割,左正右余1中间。
【解析】 由已知可得$$ \cos 2 \theta = 2 \cos ^ { 2 } \theta - 1 $$ 又$$ \tan \theta = 3 $$ 则$$ t a n ^ { 2 } \theta = 9 $$ 又$$ 1 + \tan ^ { 2 } \theta = \frac { 1 } { \cos ^ { 2 } \theta } = 1 0 $$ 故$$ \cos ^ { 2 } \t...
यदि theta(1) , theta(2) , theta3 , ..., thetan समांतर श्रेणी में है जिसका सार्वअंतर d हैं, तो सिद्ध कीजि
If secxcos5x+1=0,w h e r e0<xlt=pi/2 , find the value of x . 03:10 If 3tan(theta-15^0)=tan(theta+15^0) 0<theta<90 then theta'= 07:04 Solve that following equations : "tantheta"+"tan"(theta+pi/3)+"tan"(t... 05:31 If tan ptheta- tan q theta = 0, then the...
结果1 结果2 题目3.若$$ \tan \theta = 3 $$,则$$ \frac { \sin \theta - 2 \cos \theta } { 3 \sin \theta + \cos \theta } $$的等于 ( ) A.$$ \frac { 1 } { 1 0 } $$ B.-$$ \frac { 4 } { 5 } $$ C.$$ \frac { 2 } { 5 } $$ D.-$$ \...
首先将 $2\tan\theta = -3\tan(\theta+\frac{\pi}{4})$ 转化为正切的差公式：2\tan\theta=-3\frac{\tan\theta+\tan\frac{\pi}{4}}{1-\tan\theta\tan\frac{\pi}{4}}化简得：-3\tan^2\theta+5\tan\theta+3=0解此方程，可得 $\tan\theta=-\frac{1}{3}$ 或 $\tan\...