Maths Function

Take Your Pants Off

I cant get these 4 questions.
For 2 of them I am nearly there just cant get passed the last part. If someone has knowledge in this topic and would to like to share. Much appreciated.

Q3. (Iii)
I dont have a clue what do after deriving the second part.

Q7. I get the answer but I have no idea how to get -1, 2, 0.
As thats the value of dy dx for the 3 parts of that qs.
I input in the calculator and get completely something else. A long decimal.

Q9. Same story. I derived it and everything but cant seem to get an answer after substituting pie over 6

Q11. I have no clue whats so ever.

Thank you

harmonisch

For Q3 part(iii) you differentiated the -cos(θ/4) part incorrectly

For Qs 7 and 9 your calculator needs to be in radian mode instead of degree mode.

For Q11 you differentiate as normal and then use 2 trig identities to get the answer into the form it is looking for. You will be subbing out a cos2x for cos^2(x) - sin^2(x) and subbing out the cos^2(x) for 1-sin^2(x) after that you just tidy it up and it is finished

Take Your Pants Off

I am still having troubles with Q3 part (iii)
I get how I differentiated it wrong, its suppsed to be cos4(Power-1)thehta, but I cant progress further.

Q9, I get 2(sinx+1).cosx

skippy1977

Q3 (iii)

Don't give the 4 a negative power, easier to differentiate as is...the cos of theta/4 differentiates to minus sin theta/4 times the differentiate of theta/4...which is a quarter (the chain rule).

skippy1977

Q11