Edexcel A level Maths: 7.5 (Part 1) Maximum and Minimum values of Sin and Cos

Pearson A level Maths, Pure Year 2 Textbook (7.5)

This video gives the audience a thorough understanding of how to find the minimum or maximum value of a function involving sin or cos. I cover a variety of examples to enable the viewer to gain in depth understanding.

Follow me on Twitter and Instagram:

[acerage]

Such a great channel! KEEP IT UP it will grow very well

[larapavlova]

ur singlehandedly saving us, thank you so much, i love your channel

[gw]

Thanks so much for all your videos, they've been so helpful especially having to catch up before uni!

[habibaseif]

Your videos are very helpful sir keep it up !!
I just wanted to ask something about the question 7+2[(3cos(3x-3pie/2))]^2
I quiet didn't get the part where you gave the maximum both the values of 1 and -1 and for the minimum a zero. It confused me. Isn't the maximum value for cos a 1 and the minimum a -1? then why did we use 0 in order to get the minimum value?

[chelsea-woiy]

to find the min of 7+2(3cos(3x-3pi/2)^2 why do you make cos equal to 0? shouldnt it be -1?

[vincec]

in example 2 after you solve the equation for equal to 1 and -1 do you have to multiply every value by 2?

[shahj]

Thank you for your video! It was very helpful. However I'm stuck on one question you did: J(X): 20 -3[2sin(X+90)]^2. I approached it as 2^2=4 . 4 x -1 = -4. -4 x -3=12. 12+20=32. 32 =Max? However you put down 20. Please can you advise me on how I should approach it? thanks

[isabeltang]

This is so helpful! Are you able to do year 1 content?

[Mozzie]

5:25 why do you set cos(3x-3pi/2) equal to 0

[wr]

I these questions after I found out max and min how do I solve the equations like at 5:18

[GP-eqgh]

Hi, for a fraction, why do we have to minimize the denominator if they want us to find the maximum?

[FaizanA-mhpd]

Really helpful, but there was a particular question which really confused me.

It was find the minimum distance from the ground of a swinging swing using
40/cos(x-A)

I made the cos=-1 so that it becomes -40. Thats wrong.

I made the cos=0 and that was also incorrect. How though?

The correct answer was cos=1 but why? How would I find the maximum height then if I've exhausted all three -1, 0 and 1 values?