7.5 Day 2 Values of Trig Functions in Radians

Ex 1) If 0 ≤  < 2  and tan  = – in QII, find  rounded to 4 decimals QII  Change calc mode to RADIANS!!! Find related angle: (Positive for ref  ) RADIANS! Keep value in calculator Don’t round until last step!

Speaker & Scribe (with calculator) - Each person will be given a different trig equation and asked to find the angle - You will give your calculator to your partner - As the “scribe” you are to key in EXACTLY what the “speaker” tells you to - When you are done with your equation, you switch roles - After both partners have solved for their angles, the angles should match!

Example 2 Partner A If 0 ≤  < 2  and csc  = – in QIII, find  rounded to 4 decimals Partner B If 0 ≤  < 2  and sec  = – in QIII, find  rounded to 4 decimals θ ≈ (Don’t round until last step!)

Example 2 Partner APartner B QIII  Find related angle: (Positive for ref  ) QIII  Don’t round until last step!!

Finding Errors Ex 3) The following are 2 incorrect methods of finding θ when cot θ = Explain (write!) why each method is wrong and fix it to be correct. tan –1 should not be in the denominator! Take tan –1 of reciprocal of cot A)B) Correct:

Finding Errors Ex 4) Johnny attempts to solve the following question as shown. Decide if his work is correct or incorrect and then justify your answer. If it is incorrect, fix the error. If 0 ≤  < 2  and tan  = –2.590 in QIV, find  Step 1: θ' = tan –1 (2.590) ≈ Step 2: θ ≈ π ≈ QIV 2 His work in incorrect. θ is in QIV He should have subtracted from 2  θ ≈ 2  – ≈

Homework #717 Pg – 59 odd