Differentiating Trig Functions (1 Viewer)

[HeroicPandas]

if there are no limits, i'd IGNORE the absolute sign

 

[Menomaths]

if there are no limits, i'd IGNORE the absolute sign

Ugh used that to solve my question but still can't seem to get it... Here's the question I'm on, sketch the graph of √(1-cos²x) 0<x<2pi and evaluate integral when x= 3pi/2 and pi. I can sketch it but I don't know how to evaluate the integral part. Thanks heaps! .

 

[Menomaths]

Is it just me or my post above is cut off and ending with "(1-cos²x) 0." rather than the whole message I wrote?

 

[Smile12345]

Is it just me or my post above is cut off and ending with "(1-cos²x) 0." rather than the whole message I wrote?

No it's not just you... It appears like that for me too! But when you click 'Reply With Quote' the rest of your message appears.

 

[Menomaths]

Haha Smile even when I reply with quote the rest of my message vanishes

 

[Smile12345]

I know... hehe!!! Same, I tried it too!! Very odd. You can read the rest but it doesn't come up when posted!

 

[Najji]

Seems like the topic at the moment is the same as mine so I'll ask a question of mine here;
Find the points of intersection of the curves y=sin theta and y=cos theta for 0<pi<2pi and calculate the area between the two curves.

 

[Najji]

To see rest of the question click on reply with quote, this is quite annoying

 

[HeroicPandas]

Seems like the topic at the moment is the same as mine so I'll ask a question of mine here;
Find the points of intersection of the curves y=sin theta and y=cos theta for 0<pi<2pi and calculate the area between the two curves.

what is so hard about this, hows ur progress?

 

[Squar3root]

Challenge Question:

Integrate square root(1 - sin2x)

Ans: sinx - cosx +c

 

[Menomaths]

Challenge Question:

Integrate square root(1 - sin2x)

Ans: sinx - cosx +c

Is this 2 unit?

 

[HeroicPandas]

Is this 2 unit?

No

 

[Menomaths]

Challenge Question:

Integrate square root(1 - sin2x)

Ans: sinx - cosx +c

Got it!
square root (1-sin2x)
= square root (1-2sinucosu) (double angle formula)
= square root (sin^2x+cos^2 -2sinxcosx) (1= sin^2xcos^2x)
= square root (sin^2 -2sinxcosx+cos^2) (rearranging for (a+b)^2 formula
= square root (sinx-cosx)^2
= sinx-cosx
= -cosx -sinx + C
(Note: after all the '=' signs there is an invisible integration symbol).

 

[Menomaths]

Solved after staring at trig identities for nearly 40 minutes. Awesome question for clarifying some concepts and memorizing trig identities

 

[HeroicPandas]

sin2x = 2sinxcosx is a 3 unit trigonometric identity

 

[Menomaths]

In textbooks they should at least tell me which trig identities I need to know for the 2 unit course

 

[HeroicPandas]

In textbooks they should at least tell me which trig identities I need to know for the 2 unit course

lol, i think all u need to remember is Pythagorean identities (eg. sin^2 A + cos^2 A = 1)

complementary and supplementary angles

 

[Menomaths]

lol, i think all u need to remember is Pythagorean identities (eg. sin^2 A + cos^2 A = 1)

complementary and supplementary angles

Oh that's easy

 

[Makematics]

yep, syllabus says so. and sine rule, cosine rule, etc. the year 10 basics. i think you need to know how to solve basic trig equations though