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Core Mathematics; Trigonometry; Exercise 6D

Need help with the following questions. Please explain all steps little by little.
1. Solve the following equation in the given interval:
sec^2[theta] = 3tan[theta], 0<(and equal to) [theta] <(and equal to) 360º

2. Given that x = sec[theta] + tan [theta], show that 1/x = sec[theta]-tan[theta]

3. Given that 2sec^2[theta] - tan^2[theta] = p show that cosec^2[theta] = p-1/p-2, P cannot equal 2.

Please explain each step. Thanks a lot.
Reply 1
Mohit_C
Need help with the following questions. Please explain all steps little by little.
1. Solve the following equation in the given interval:
sec^2[theta] = 3tan[theta], 0<(and equal to) [theta] <(and equal to) 360º

Please explain each step. Thanks a lot.


sec^2[x] = 3tan[x],
sec^2x=tan^2x +1
tan^2x + 1 = 3tanx
0=tan^2x - 3tanx + 1 y=tanx
0= y^2 - 3y + 1
erm quadratic formula...
Reply 2
The factorisation contains an error.

2y x y = 2y^2
Reply 3
lol yh i jus noticed
Reply 4
Thats right.
Reply 5
Mohit_C
Need help with the following questions. Please explain all steps little by little.
1. Solve the following equation in the given interval:
sec^2[theta] = 3tan[theta], 0<(and equal to) [theta] <(and equal to) 360º

.


I worked as far as one angle. There are several other solutions
Reply 6
Theres an error in yours aswel:
You have got :

tan^2[x] + 1 = 3tan[x] thn you got
tan^2[x] - 3tan[x] - 1=0 shouldnt it be +1 ???
Reply 7
Jordan7
Theres an error in yours aswel:
You have got :

tan^2[x] + 1 = 3tan[x] thn you got
tan^2[x] - 3tan[x] - 1=0 shouldnt it be +1 ???


I can't see the error. Which line is it in.
Reply 8
the 6th line of your working
Reply 9
Jordan7
the 6th line of your working

Are you winding me up?

I have written plus one.
Reply 10
o ok sorry its just the vertical line of the + is very very faint, on myn anyway.
Reply 11
Thanks guys, need help with the remaining ones, especially the last one which doesn't seem to make any sense whatsoever to me.
Reply 12
Mohit_C
Need help with the following questions. Please explain all steps little by little.

13. Given that 2sec^2[theta] - tan^2[theta] = p show that cosec^2[theta] = p-1/p-2, P cannot equal 2.

Please explain each step. Thanks a lot.


2sec^2[theta] - tan^2[theta] = p
2(tan^2x + 1) - tan^2x = p
tan^2x + 2 = p

cosec^2x= 1+ cot^2x
cosec^2x = 1 + (1/tan^2x)
1 = tan^2x / tan^2x
cosec^2x= tan^2x/tan^2x + 1/tan^2x
cosec^2x= (tan^2x +1) / ( tan^2x)
cosec^2x= (p-1) / (p-2)
Reply 13
Thanks Jordan7. I have a little question. On question 2, where you had to find 1/x, the book used the idea of rationalizing....can this be done with trigonometric functions?