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Original post by Qer
where that 2 goes
i know first to take inverse of sin sqroot 2/2
then what to do of 2 with that?
where that 2 goes
i know first to take inverse of sin sqroot 2/2
then what to do of 2 with that?
sin(2x) = 2 cos x sin x
Original post by Zacken
sin(2x) = 2 cos x sin x
can you please show me working?. it will be easier for me to understand
Original post by Qer
can you please show me working?. it will be easier for me to understand
No. Tell me what you've done so far. What is arcsin(sqrt(2)/2)? What is 2 times that? What is sin of that?
Original post by Zacken
No. Tell me what you've done so far. What is arcsin(sqrt(2)/2)? What is 2 times that? What is sin of that?
is it like that
2 arcsin sqroot 2/2= 2 X 1/4pi = 1/2 pi
sin( 1/2 pi)=1
not sure that it is right?
Original post by Qer
is it like that
2 arcsin sqroot 2/2= 2 X 1/4pi = 1/2 pi
sin( 1/2 pi)=1
not sure that it is right?
2 arcsin sqroot 2/2= 2 X 1/4pi = 1/2 pi
sin( 1/2 pi)=1
not sure that it is right?
It is. See, all you had to do was try it yourself.
Original post by Zacken
It is. See, all you had to do was try it yourself.
can i ask some more questions?
Original post by Qer
can i ask some more questions?
can i ask some more questions?
Sure. As long as you lay out your current working/thoughts for them.
Original post by Zacken
Sure. As long as you lay out your current working/thoughts for them.
so
i am ok with part a . as we can see from graph
for part b
i
cos^2k =1- sin^2k
taking sqroot
cos k= 1- sin k
the book shows answer is +- sqroot(1-sin^2 k)
why they dont cancel sqroot?
part c doesnt make any sense to me
Original post by Qer
so
i am ok with part a . as we can see from graph
for part b
i
cos^2k =1- sin^2k
taking sqroot
cos k= 1- sin k
the book shows answer is +- sqroot(1-sin^2 k)
why they dont cancel sqroot?
part c doesnt make any sense to me
so
i am ok with part a . as we can see from graph
for part b
i
cos^2k =1- sin^2k
taking sqroot
cos k= 1- sin k
the book shows answer is +- sqroot(1-sin^2 k)
why they dont cancel sqroot?
part c doesnt make any sense to me
sqrt(1-sin^2 k) is not the same thing as 1 - sin k.
Do you think that sqrt(1-0.5^2) = 1 - 0.5?
Original post by Zacken
sqrt(1-sin^2 k) is not the same thing as 1 - sin k.
Do you think that sqrt(1-0.5^2) = 1 - 0.5?
Do you think that sqrt(1-0.5^2) = 1 - 0.5?
ok
that make sense now
Original post by Qer
ok
that make sense now
that make sense now
You know that if 0<k<pi/2 then cos k is a positive number, which is why cos k = sqrt(1- sin^2 k)
If -pi/2 < k < 0, what is the sign of cos k? Check a graph. Is it under/below the k-axis in that interval?
Original post by Zacken
You know that if 0<k<pi/2 then cos k is a positive number, which is why cos k = sqrt(1- sin^2 k)
If -pi/2 < k < 0, what is the sign of cos k? Check a graph. Is it under/below the k-axis in that interval?
If -pi/2 < k < 0, what is the sign of cos k? Check a graph. Is it under/below the k-axis in that interval?
how i make graph of function cos k = sqrt(1- sin^2 k)?
Original post by Qer
how i make graph of function cos k = sqrt(1- sin^2 k)?
No, make a graph of the function cos k.
dran
graph is in second quadrant ( above the axes) so it is positive
Original post by Zacken
You know that if 0<k<pi/2 then cos k is a positive number, which is why cos k = sqrt(1- sin^2 k)
If -pi/2 < k < 0, what is the sign of cos k? Check a graph. Is it under/below the k-axis in that interval?
If -pi/2 < k < 0, what is the sign of cos k? Check a graph. Is it under/below the k-axis in that interval?
graph is in second quadrant ( above the axes) so it is positive
Original post by Qer
drangraph is in second quadrant ( above the axes) so it is positive
Right, so there's no difference to your answer. cos k = sqrt(1 - sin^2 k)
You just need to rewrite sin^2 k in terms of x.
Original post by Zacken
Right, so there's no difference to your answer. cos k = sqrt(1 - sin^2 k)
You just need to rewrite sin^2 k in terms of x.
You just need to rewrite sin^2 k in terms of x.
there is also tan in par b
is this answer for both of them?
Original post by Qer
there is also tan in par b
is this answer for both of them?
is this answer for both of them?
You tell me. Is tan k positive for 0<k<pi/2? What about for -pi/2 < k < 0?
Original post by Zacken
You tell me. Is tan k positive for 0<k<pi/2? What about for -pi/2 < k < 0?
Is tan k positive for 0<k<pi/2?
it is positive
-pi/2 < k < 0?
in that range it is below the axes so it is negative?
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