MHB Trigonometric Question sin^2(180-x) cosec(270+x) + cos^2(360-x) sec(180-x)

  • Thread starter Thread starter Yazan975
  • Start date Start date
  • Tags Tags
    Trigonometric
AI Thread Summary
The discussion revolves around simplifying the expression sin^2(180-x) cosec(270+x) + cos^2(360-x) sec(180-x). The user correctly identifies that sin^2(180-x) simplifies to sin^2(x) and cos^2(360-x) simplifies to cos^2(x). They note that the sine and cosine terms cancel with their respective cosecant and secant functions, leading to a simplified form. However, the user is confused as their result does not match the answer sheet, which states the answer is -sec(x). Further assistance is requested to complete the simplification correctly.
Yazan975
Messages
30
Reaction score
0
View attachment 9012

In this question, I tried this:

sin^2(180-x) cosec(270+x) + cos^2(360-x) sec(180-x), where cosec(x) = 1/sin(x) and sec(x) = 1/cos(x)

-sin^2(180-x) = sin^2(x) and cos^2(x) = cos^2(x)

-The sin^2 and the 1/sin(x) cancle out along with the cos^2 and the 1/cos(x)

Therefore, I am left with sin(x)(270+x) + cos(x)(180-x)

This looks wrong. The answer on the answer sheet is -sec(x). I ask you for help please.
 

Attachments

  • Screen Shot 2019-05-17 at 7.24.45 PM.png
    Screen Shot 2019-05-17 at 7.24.45 PM.png
    23.6 KB · Views: 130
Mathematics news on Phys.org
$\csc(270+x) = \dfrac{1}{\sin(270+x)} = \dfrac{1}{\sin(270)\cos{x}+\cos(270)\sin{x}} = \dfrac{1}{-\cos{x}}$

$\sec(180-x) = \dfrac{1}{\cos(180-x)} = \dfrac{1}{\cos(180)\cos{x} + \sin(180)\sin{x}} = \dfrac{1}{-\cos{x}}$

...

$\dfrac{\sin^2{x}}{-\cos{x}} + \dfrac{\cos^2{x}}{-\cos{x}}$

can you finish from here?
 
Suppose ,instead of the usual x,y coordinate system with an I basis vector along the x -axis and a corresponding j basis vector along the y-axis we instead have a different pair of basis vectors ,call them e and f along their respective axes. I have seen that this is an important subject in maths My question is what physical applications does such a model apply to? I am asking here because I have devoted quite a lot of time in the past to understanding convectors and the dual...
Fermat's Last Theorem has long been one of the most famous mathematical problems, and is now one of the most famous theorems. It simply states that the equation $$ a^n+b^n=c^n $$ has no solutions with positive integers if ##n>2.## It was named after Pierre de Fermat (1607-1665). The problem itself stems from the book Arithmetica by Diophantus of Alexandria. It gained popularity because Fermat noted in his copy "Cubum autem in duos cubos, aut quadratoquadratum in duos quadratoquadratos, et...
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
Back
Top