Back
to top
Higher maths problem
Watch this thread
Announcements
Page 1 of 1
Go to first unread
Skip to page:
Rox17
Badges:
12
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#1
You have to solve for cosTPQ. Idk what to do, I did cosTPQ=cos(2x + 90) and did the expansion but I got a negative number? Please helppp
https://ibb.co/s58fHt4
https://ibb.co/s58fHt4
0
reply
mqb2766
Badges:
19
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#2
Report
#2
(Original post by Rox17)
You have to solve for cosTPQ. Idk what to do, I did cosTPQ=cos(2x + 90) and did the expansion but I got a negative number? Please helppp
https://ibb.co/s58fHt4
You have to solve for cosTPQ. Idk what to do, I did cosTPQ=cos(2x + 90) and did the expansion but I got a negative number? Please helppp
https://ibb.co/s58fHt4
Assuming the diagram is correct and Im understanding the original problem, why not just calculate x, then use it to get the actual angle you want.
0
reply
Rox17
Badges:
12
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#3
I can't get you the original question bc it's in a textbook and I don't have it with me. I also should've mentioned that this is non calculator
https://ibb.co/XsDqcrV
https://ibb.co/XsDqcrV
0
reply
mqb2766
Badges:
19
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#4
Report
#4
(Original post by Rox17)
I can't get you the original question bc it's in a textbook and I don't have it with me. I also should've mentioned that this is non calculator
https://ibb.co/XsDqcrV
I can't get you the original question bc it's in a textbook and I don't have it with me. I also should've mentioned that this is non calculator
https://ibb.co/XsDqcrV
Note that as its > 90, youd expect cos() to be negative. However, you seem to double the trig value rather than doubling the angle, then taking the trig of that.
0
reply
Rox17
Badges:
12
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#5
How do I double just the angle? I think I'm supposed to calculate the exact value, not the actual angle. I did cos90=0 since I took the 90 from the right angle at the top
0
reply
mqb2766
Badges:
19
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#6
Report
#6
(Original post by Rox17)
How do I double just the angle? I think I'm supposed to calculate the exact value, not the actual angle. I did cos90=0 since I took the 90 from the right angle at the top
How do I double just the angle? I think I'm supposed to calculate the exact value, not the actual angle. I did cos90=0 since I took the 90 from the right angle at the top
Last edited by mqb2766; 1 month ago
0
reply
Rox17
Badges:
12
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#7
Naan102
Badges:
4
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#8
Rox17
Badges:
12
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#9
No I didnt😭😭it's something to do w that cos90 i think bc it makes the answer negative, ill ask my teacher od Wednesday if I still can't figure it out
Last edited by Rox17; 1 month ago
0
reply
mqb2766
Badges:
19
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#10
Report
#10
(Original post by Rox17)
No I didnt😭😭it's something to do w that cos90 i think bc it makes the answer negative, ill ask my teacher od Wednesday if I still can't figure it out
No I didnt😭😭it's something to do w that cos90 i think bc it makes the answer negative, ill ask my teacher od Wednesday if I still can't figure it out
Have you written the identity out clearly for cos(2x + 90)? I.e. try getting the sin(2x) part correct.
0
reply
Rox17
Badges:
12
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#11
(Original post by mqb2766)
As above, why do you think that cos(2x+90) being negative is wrong?
Have you written the identity out clearly for cos(2x + 90)? I.e. try getting the sin(2x) part correct.
As above, why do you think that cos(2x+90) being negative is wrong?
Have you written the identity out clearly for cos(2x + 90)? I.e. try getting the sin(2x) part correct.
0
reply
mqb2766
Badges:
19
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#12
Report
#12
(Original post by Rox17)
Bc it's a triangle and I'm pretty sure it can't be a negative angle right? I've rewritten it with the correct 2x part but the cos90 makes the first part 0 so the second part becomes negative? Or am I being stupid😭
Bc it's a triangle and I'm pretty sure it can't be a negative angle right? I've rewritten it with the correct 2x part but the cos90 makes the first part 0 so the second part becomes negative? Or am I being stupid😭
In your identity, the cos(90) is indeed 0, so the value of cos(2x+90) is determined by the second part.
0
reply
Rox17
Badges:
12
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#13
(Original post by mqb2766)
sin(x) and/or cos(x) is certainly not negative. But the angle is 2x + 90, so what must the sign of cos(2x + 90) be?
In your identity, the cos(90) is indeed 0, so the value of cos(2x+90) is determined by the second part.
sin(x) and/or cos(x) is certainly not negative. But the angle is 2x + 90, so what must the sign of cos(2x + 90) be?
In your identity, the cos(90) is indeed 0, so the value of cos(2x+90) is determined by the second part.
0
reply
mqb2766
Badges:
19
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#14
Report
#14
(Original post by Rox17)
But the second part is taken away from the first part and there's no negatives in it so it's always gonna be negative?
But the second part is taken away from the first part and there's no negatives in it so it's always gonna be negative?
so cos(2x+90) is indeed negative.
https://sites.google.com/view/tlmath...e3-trig-graphs
If you don't have your textbook handy where the question comes from, its really worth waiting until you do have it to go over the bits properly rather than being led too much to the answer.
0
reply
Naan102
Badges:
4
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#15
Report
#15
(Original post by Rox17)
No I didnt😭😭it's something to do w that cos90 i think bc it makes the answer negative, ill ask my teacher od Wednesday if I still can't figure it out
No I didnt😭😭it's something to do w that cos90 i think bc it makes the answer negative, ill ask my teacher od Wednesday if I still can't figure it out
1
reply
Rox17
Badges:
12
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#16
(Original post by Naan102)
Can u post the question when u have it. Thanks
Can u post the question when u have it. Thanks
0
reply
Rox17
Badges:
12
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#17
(Original post by mqb2766)
2x+90 > 90
so cos(2x+90) is indeed negative.
https://sites.google.com/view/tlmath...e3-trig-graphs
If you don't have your textbook handy where the question comes from, its really worth waiting until you do have it to go over the bits properly rather than being led too much to the answer.
2x+90 > 90
so cos(2x+90) is indeed negative.
https://sites.google.com/view/tlmath...e3-trig-graphs
If you don't have your textbook handy where the question comes from, its really worth waiting until you do have it to go over the bits properly rather than being led too much to the answer.
I put the inverse cos of the negative answer I got through a calculator just to check and it turned out positive
Oops don't mind the surded 13 at the end I forgot to scribble it out
https://ibb.co/ThbPNby
Last edited by Rox17; 1 month ago
1
reply
mqb2766
Badges:
19
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#18
Report
#18
(Original post by Rox17)
OHH OK I THINK I GOT IT NOW I thought I found the angle but I realised I was finding what cos = 🤦*♀️🤦*♀️🤦*♀️🤦*♀️
I put the inverse cos of the negative answer I got through a calculator just to check and it turned out positive
https://ibb.co/ThbPNby
OHH OK I THINK I GOT IT NOW I thought I found the angle but I realised I was finding what cos = 🤦*♀️🤦*♀️🤦*♀️🤦*♀️
I put the inverse cos of the negative answer I got through a calculator just to check and it turned out positive
https://ibb.co/ThbPNby
Last edited by mqb2766; 1 month ago
0
reply
Rox17
Badges:
12
Rep:
?
You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#19
(Original post by mqb2766)
Looks about right. Note for the cos() being 12/13, it imples sin() is 5/13 as 5: 12:13 is a pythagorean triple
Looks about right. Note for the cos() being 12/13, it imples sin() is 5/13 as 5: 12:13 is a pythagorean triple
0
reply
X
Page 1 of 1
Go to first unread
Skip to page:
Quick Reply
