can someone please help me with trigonometric substitutions?
it's much easier if you just post the specifics
I do that and no one answers me
sometimes we may not know or are just caught up on something at the moment, we can always check back on material posted
Use trigonometric substitution to write 3= radical (36-x^2) as a trigonometric function of theta, where -pi/2<theta<pi/2 given x=6 sin theta. Use the function to find the value of sin theta.
hmmm not sure I follow that... can you post a quick screenshot of the material?
do you have any idea how to solve that?
I'm incredibly lost.
\(\bf 3 = \sqrt{(36-x^2)}\qquad \qquad x = 6sin(\theta)\\ \quad \\ 3 = \sqrt{(36-x^2)}\implies 3 = \sqrt{(36-(6sin(\theta))^2)}\\ \quad \\ \textit{squaring both sides}\\ \quad \\ (3)^2 = \left(\sqrt{(36-(6sin(\theta))^2)}\right)^2\implies (3)^2 = \sqrt{[36-(6sin(\theta))^2]^2}\\ \quad \\ 9=36-(6sin(\theta))^2\implies (6sin(\theta))^2=36-9\implies (6sin(\theta))^2=27\\ \quad \\ \textit{now taking square root to both sides}\\ \quad \\ \sqrt{(6sin(\theta))^2}=\sqrt{27}\implies 6sin(\theta)=\sqrt{27}\\ \quad \\ sin(\theta)=\cfrac{\sqrt{27}}{6}\)
\(\bf \color{blue}{27 = 3\times 3\times 3\implies 3^2\times 3}\qquad thus\\ \quad \\ sin(\theta)=\cfrac{\sqrt{27}}{6}\implies sin(\theta)=\cfrac{\sqrt{3^2\times 3}}{6}\implies sin(\theta)=\cfrac{\cancel{3}\sqrt{ 3}}{\cancel{6}}\\ \quad \\ \implies sin(\theta)=\cfrac{\sqrt{ 3}}{2}\)
thank you so much! I actually understood that!
yw
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