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What is the maximum and minimum value of sin x +cos x?
Let y= sin x + cos x
dy/dx=cos x- sin x
For maximum or minimum dy/dx=0
Setting cosx- sin x=0
We get cos x = sin x
x= π/4, 5 π/4 ———-
Whether these correspond to maximum or minimum, can be found from the sign of second derivative.
d^2y/dx^2=-sin x - cos x=-1/√2 –1/√2 (for x=π/4) which is negative. Hence x=π/4 corresponds to maximum.For x=5 π/4
d^2y/dx^2=-(-1/√2)-(-1/√2)=2/√2 a positive quantity. Hence 5 π/4 corresponds to minimum
Maximum value of the function
y= sin π/4 + cos π/4= 2/√2=√2
Minimum value is
Sin(5 π/4)+cos (5 π/4)=-2/√2=-√2
sin (200)0 + cos (200)0 is
Because both sin 2000 and cos 2000 lies in 3rd quadrant. In 3rd quadrant values of sin and cos are negative.
If cos(-1) x + cos(-1) y = 2 π, then the value of sin(-1) x + sin(-1) y is
If cos(-1) x + cos(-1) y = 2 π, then the value of sin(-1) x + sin(-1) y = π−2 π= −π.
Domain of f(x) = sin−1 x −sec−1 x is
Since sin−1 x is defined for |x|⩽1, and sec−1 x is defined for |x|⩾1,therefore,f(x) is defined only when|x|=1.so, Df = {−1,1}.
The value of sin is
Put therefore the given expressionis sin2 θ= 2sin θcos θ
If 5 sin θ= 3, then is equal to
= [(5/4) + (3/4)] / [(5/4) - (3/4)] =(8/4) / (2/4) =4
If sin A + cos A = 1, then sin 2A is equal to
(sinA+cosA)2 = sin2 A+cos2 A+2sinAcosA =11+sin2 A=1sin2 A=0. (because Sin 2A = 2sin A cos A)
If θ= cos-1, then tan θis equal to
Therefore, tan θ=
The number of solutions of the equation cos-1 (1-x) - 2cos-1 x = π/2 is
As no value of x in (0, 1) can satisfy the given equation.Thus, the given equation has only one solution.
tan (sin−1 x) is equal to
If x ∈R, x ≠0, then the value of sec θ+ tan θis
The value of cos 1050 is
If cos(2sin−1 x) = 1/9 then x =
Put
sin-1 x = θ⇒x = sin θ
cot (cos−1 x) is equal to
Put, cos-1 x = θ⇒x = cos θ⇒cos θ
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