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Anon25 [30]
3 years ago
7

2 tan^2 x-sec x+1 =0​

Mathematics
2 answers:
Nataly [62]3 years ago
3 0

Write it with only cos function:

2 * (sin x /cos x)² - 1/cos x + 1 =0

(remember that cos x ≠0)

2sin²x/cos²x - 1/cos x + 1 = 0 /*cos²x

2sin²x - cos x +cos² x = 0

2(1-cos²x)-cos x+cos²x=0

2-2cos²x-cos x + cos²x=0

-cos²x-cos x+2=0 /*(-1)

cos²x+cos x-2=0

I used only these formulas:

tan x = sin x / cos x

sec x = 1/cos x

sin²x + cos² x = 1 (then cos²x = 1-sin²x).

Okay. We've got easy quadratic equation. Substitute t = cos x, remember that -1≤ t ≤1 and t≠0 is a domain.

t²+t-2=0

∆=1²-4*(-2)*1=1+8=9

√∆=3

t1 = (-1+3)/2 = 1 - it is in domain

t2 = (-1-3)/2 = -2 - it's not in domain.

So we reached only cos x = 1.

The solution of this equation is x = 2πk where k is an integral

shusha [124]3 years ago
3 0

Answer:

x = 0, 360   ( 0 = < x  <= 360).

Step-by-step explanation:

2 tan^2 x-sec x+1 =0​

Substituting  tan^2 x =  sec^2 x - 1:

2(sec^2 x - 1) - sec x + 1 = 0

2sec^2 x - 2 - sec x + 1 = 0

2 sec^2 x - sec x - 1 = 0

(2 sec x + 1)(sec x - 1) = 0

sec x = -1/2 ,  sec x = 1

1/cos x = -1/2 , cos x = 1

cos x = -2 ( undefined)= so we ignore this),   cos x = 1.

So x = arcos(1) = 0,  360.

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If carlos did some work and got 3x + 2x - 6 = 24 what mistake did he make
Makovka662 [10]

Carlos made the mistake that he did not combine like terms (3 x and 2 x) properly and did not use addition property of equality.

<u>Step-by-step explanation:</u>

Carlos did the work as 3 x + 2 x - 6 = 24

We need to find his mistake that he made in above given.

Here, he did not add the like terms (3 x and 2 x)

             3 x + 2 x = 5 x

Therefore, his work should be

             5 x  - 6 = 24

Also, he did not use addition property of equality. It means the equation remains same even though the same number gets added on both sides. It would be

                          5 x  - 6 = 24

                                 + 6 = + 6

                          -----------------------

                           5 x = 30

Dividing 30 by 5, we get answer as '6'. Hence,

                            x=\frac{30}{5} = 6

So, stated the above two are the mistakes found in carlos work.

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